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A ' -•^''vrvf ;t* /^^3 v(> U I D E THE STUDY OF INSECTS / AND A TREATISE ON THOSE INJURIOUS AND BENEFICIAL TO CROPS FOR THE USE OF COLLEGES, FARM-SCHOOLS, AND AGRICULTURISTS A. S3 PACKARD, Jr., M.D. WITH FIFTEEN PLATES AND SIX HUNDRED AND SEVENTY WOOD CUTS, EIGHTH EDITION. HEN^ ftOLT ANDA^jfiOMPANY BOSTON : ■■SSfES'>'LAURIAT "7883. Copyright by A. S. PACKARD, Jr.., 18G9 animbs, Proceedings of the Boston Society of Natural History, 1867) has shown that antero-posterior symmetry is very marked in Articulates. In the .idjoining figure of Jara (Fig. 2) the longi- tudinal lines illustrate what is meant by bilateral symmetry, and the transverse, lines "fore and aft" symmetry. The two antero-posterior halves of the body are very symmetrical in the Crustacean genera Jiera, Guineas, PorcelHo, and other Crustacea, and also among the Myriopods, Scutigera, I'olydesmus, " in which the limbs are repeated oppositely, though with different degrees of inequality, from the centre of the body backwards and forwards." "Leuckart and Van Beneilen have shown that Mysis has an ear in the last segment, and Schmidt has described an eye in the same part in a worm, Ampliicora." — From Wytnan. Fig. S represents an ideal section of a Worm. / indicates the skin, or mus- cular body-wall, which on each side is produced into one or more fleshy tubercles, Bbually tipped with bristles or hairs, which serve as organs of locomotion, and THE CLASS OF INSECTS. 3 ramify throughout the whole interior of the animal, and con- nect with breatliing pores (stigmata) in the sides of tlie bod}'. They do not breathe through the mouth as do the higher ani- mals. The tracheae and blood-vessels follow closely the same course, so that the aeration of the blood goes on, apparently, over the whole interior of the body, not being confined to a single region, as in the lungs of the vertebrate animals. Thus it is by observing the general form of the body-walls, and the situation of the diflerent anatomical systems, both in relation to themselves and the walls of the body, or crust, which surrounds and protects the more delicate organs within, that we are able to find satisfactory characters for isolating, in our definitions, the Arthropoda from all other animals. We shall perceive more clearly the ditfereiices between the two branches of articulated or jointed animals, namely, tlie Worms and the Arthropoda, by examining their young often as lungs. The nervous cord {a) rests on the floor of the cylinder, sending a filament into the oar-like feet (./"), and also aronnd the intestine or stomach (fc), to ;i supplementary cord (rf), whicli is situated just over the intestine, and under tlu; heart or dorsal vessel (c). The circle c and e is a diagram of the circulatory sys- tem; c is the dorsal vessel, or heart, from the side of which, in each ring, a small vessel is sent downwards and around to c, the ventral vessel. — Original. Fig. 4. An ideal section of a Bee. Here the crust is dense and thick, to which strong muscles are attached. On the upper side of the ring the wings grow out, while the legs are inserted near the under side. The trachea? {d) enter through the stiyma, or breathing pore, situated just under the wing, and their branches sub- divide and are distributed to the wings, with their Jive pviucipal veius as indicated THE CLASS OF INSECTS. Stages, from the time of their exclusion from the egg, imtil they pass into mature life. A more careful study of this period than we are now able to enter upon would show us how much alike the young of all Arthropods are at first, and how soon they begin to differ, and assume the shape characteristic of their branch. Most Worms, after leaving the egg, are at first like some infusoria, being little sac-like animalcules, often ciliated over nearly the entire surface of the infinitesimal body. Soon this sac-like body grows longer, and con- tracts at intervals ; the intervening parts become unequally enlarged, some segments, or rings, formed by the contraction of the bod^^-walls, greatly exceeding in size those next to them ; and it thus assumes the appearance of being, more or less equally ringed, as in the young Terebella (Fig. 5), where the ciliae are restricted to a single circle surrounding the body. Gradually (Fig. 6) the cilise disap- pear and regular locomotive organs, consisting of minute paddles, grow out from each side ; feelers (antenna), jaws, and eyes (simple rudi- mentar}^ eyes) appear on the few front rings of the body, which are grouped b}^ themselves into a sort of head, though it is difficult, in a large proportion of the lower worms, for un- skilled observers to distinguish the head from the tail. Thus we see throughout the growth of the worm, no attempt at subdividing the body into regions, each endowed with its peculiar I , functions ; but only a more perfect s^^stem of ' rings, each relatively ver^- equalh' developed, m the figure, also to the dorsal vessel (c), the intestine (6), and the nervous cord (n). The tracheaB and a nervous lilameut are also sent into the legs and to the wings. The tracheae are also distributed to the dorsal vessel and intestine by numerous branches which serve to hold them in place. — Orir/inal. Fig. 5. Young Terebella, soon alter leavnig the egg. — From A. Agassiz. Fig. 6 represents the embryo of a worm (Autolytus comutus) at a Inter stagv of growth, a is the middle tentairle of the head ; e, one of the posterior tentacles ; h, the two eye-spots at the base of the hinder pair of feelers ; c is one of a row of our-lilie organs (cirri) at the base of which are inserted the locomotive bristle.s, THE CLASS OF INSECTS. 5 but all becoming respectively more complicated. For exampie. in the Earth-worm (Lumbricus) , each ring is distinguishable into an upper and under side, and in addition to these a well- marked side-area, to which, as for example in marine worms (e. g. Nereis)^ oar-like organs are attached. In most worms eye-spots appear on the front rings, and slender tentacles grow out, and a pair of nerve-knots (ganglia) are apportioned to each ring. In the Crustaceans, such as the fresh-water Crawfish (Asta- c?(s), as shown by the German naturalist Rathke ; and also in the earliest stages of the Insect, the body at once assumes a worm-like form, thus beginning its embryonic life from the goal reached by the adult worm. The young of all Crustaceans (Fig. 7) first begin life in the egg as oblong flattened worm-like bodies, each end of the body being alike. The young of the lower Crustaceans, such as the Barnacles, and some marine forms (Copepoda), and some lowly organized parasitic species inhabiting the gills of fishes, are hatched as microscopic embryos which would readily be mistaken for young mites (Acarina) . In the higher Crus- taceans, such as the fresh-water Crawfish, the young, when hatched, does not greatly differ from the parent, as it has passed through the worm-like stage within the egg. Fig. 7 represents the young of the fresh- water Lobster (Crawfish) before leaving the egg. The body is divided into rings, ending in lobes on the sides, which are the rudiments of the limbs, b is the rudiment of the eye- stalk, at the end of wiiich is the eye ; a is the fore antennae ; c is the hind antennae ; d is one of the maxilla-feet ; e is the first pair of true feet destined in the adult to form the large "claw." Thus the eye-stalks, antemiie, claws, and legs are moulded upon a common form, and at first are scarcely distin- with the cirri serving as swimming and locomotive organs ; d, the caudal styles, or tail-feelers. In this figure we see how slight are the differences between the feelers of the head, the oar-like swimming organs, and the caudal filaments ; we can easily see that they are but modifications of a common form, and all arise from the common limb-bearing region of the body. The alimentary canal, with the proventriculus, or anterior division of the stomach, occupies tlie middle of the body; while the mouth opens on the under side of the head. — From A. Agassis. " Fig. 7. Embryo of the Crawfish. — From Rcithke. 1* THE CLA.SS OF INSECTS. j^iiishable from each other. Here we see the embryo divided iato a head-thorax and a tail. It is the same with Insects. Within the egg at the dawn of life they are flattened oblong bodies curved upon the yelk- mass. Before hatching they become more cylindrical, the limbs bud out on the sides of the rings, the head is clearly demarked, and the young caterpillar soon steps forth from the egg-shell ready armed and equipped for its riotous life. As will be seen in Fig. 8, the legs, jaws, and antennre are first started as buds from the side of the rings, being simply elongations of the body-wall, which bud out, become larger, and Anally jointed, until the buds arising from the thorax or abdomen become legs, those from the base of the head be- come jaws, while the antennse and palpi sprout out from the front rings of the head. Thus while the bodies of all articulates are built up from a common em- bryonic form, their appendages, which are so diverse, when we compare a Lobster's claw with an Insect's antenna, or a Spider's spinneret with the hinder limbs of a Centipede, are yet but modifications of a common form, adapted for the different uses to which tliey are put by these animals. Fig. 8. A Ciiddis, or C;ise-lly (.^^y■it'lc^(les) iu the ejjg, with pari of the yolk (.r) not yet inc-loscd within the hixly-walls. ti, anteniiEe ; between a and h the mandi- bles; b, maxilla; c, labium; il, the separate eye-spots (ocelli), which afterwards in- '•rease trrcatly in number and unite to form the compound eye. The "neck" or junction of the head with tlie thorax is seen at the front part of the yolk-mass; e, the three pairs of legs, which are folded once on themselves ;/, the pair of anal \eg» attached to the tenth ring of the abdomen, as seen in cateri)illars, which form long antenna-like filaments in the Cockroach ani i> parts in subservience to its peculiar and higher ends in the animal economy. The Crustacean, of which the Shrimp (Fig. 9) is a typical example, is com- posed of a determinate number (21) of rings which Fig, 9. are gathered into two regions ; the head-thorax (cephalo- Ihorax) and hind -body, or abdomen. In this class there is a broad distinction between the anterior and posterior ends f)f the body. The rings are now grouped into two regions, and the hinder division is subordinate in its structm'c aud Fig. 9. A Shrinii). /'((Ui/tiliiK (aniulirnriiis. ct, ceiihalothorax: ?>,.!i^''<'"it'"- 8 THE CLASS OF INSECTS. uses to the forward portion of the body. Hence the nervous power is transferred in some degree towards the head ; the cephalothorax containing the nervous centres from which nerves are distributed to the abdomen. Nearly all the organs perform- ing the functions of locomotion and sensation reside in the front region ; while the vegetative functions, or those concerned in the reproduction and nourishment of the animal, are mostly carried on in the hinder region of the body (the abdomen). The typical Crustacean cannot be said to have a true head, in distinction from a thorax bearing the organs of locomotion, but rather a group of rings, to wdiich are appended the organs of sensation and locomotion. Hence we find the appendages of this region gradually changing from antennae and jaws to foot-jaws, or limbs capable of eating and also of locomotion ; they shade into each other as seen in Fig. 9. Sometimes the jaws become remarkably like claws ; or the legs resemble jaws at the base, but towards their tips become claw-like ; gill-like l)odies are sometimes attached to the foot-jaws, and thus, as stated b}' Professor J. D. Dana in the introduction to his great work on the Crustacea of the United States Exploring Expedi- tion, the typical Crustaceans do not haA'e a distinct head, but ratlier a "head-thorax" (cephalothorax). WHien we rise a third and last step into the world of Insects, we see a completion and final development of the articu- late plan which has been but obscurely hinted at in the tw^o lowest classes, the "Worms and Crustaceans. Here we first meet with a true head, separate in its structure and functions from the thorax, which, in its turn, is clearly distinguishable from the third region of the body, the abdomen, or hind-body. These three regions, as seen in the Wasp (Fig. 10), are each provided with three distinct sets of organs, each having distinct functions, though all are governed by and minister to the brain force, now in a great measure gathered up from the Fig. 10. posterior rings of the body, and in a more concentrated form (the brain being larger than in the lower articulates) lodged in the head. Here, then, is a centralization of parts headwards ; thev arc Fig. 10. Philanthus veiiHlabris Fa.hv. A Wood-wasp. — From Say. COMPOSITION OF THE INSECT-CRUST. 9 brought as if towards a focus, and that focus the head, whicli is the meaning of the term " cephalization," proposed by Pro- fessor Dana.* Ring distinctions have given way to regional distinctions. The former characterize the Worm, tlie latter the Insect. In other words, the division of the body into three parts, or regions, is in the insect, on the whole, better marked than the division of any one of those parts, except the abdo- men, into rings. Composition of the Insect-crust. Before describing the composition of the body-wall, or crust, of the Insect, let us briefly review the mode in which the same parts are formed in the lower classes, the Worms and Crustaceans. We have seen that the typical ring, or segment (called by authors zoonule, zoonite, or somite, meaning parts of a body, though we prefer the term arthromere, denoting the elemental part of a jointed or articulate animal), consists of an upper (tergite), a side (pleurite), and an under piece (sternite). This is seen in its greatest simplicity in the Worm (Fig. 2), where the upper and ventral arcs are separated by the pleural region. In the Crus- tacean the parts, hardened by the deposition of chitine and therefore thick and unyielding, have to be farther subdivided to secure the necessary amount of freedom of motion to the body and legs. The upper arc not only covers the back of the ani- mal, but extends down the sides ; the legs are jointed to the ejnmera, or flanks, on the lower arc ; the episternum is sitiiated between the epimerum and sternum ; and the sternum, form- ing the breast, is situated between the legs. In the adult, there- fore, each elemental ring is composed of six pieces. It should, however, be borne in mind that the tergum and ster- * In two papers on the Classification of Animals, published in the American Journal of Science and Arts, Second Series, a^oI. xxxv, p. 05, vol. xxxvi, July, 1863, and also in his earlier paper on Crustaceans, " the principle of cephalization is shown to be exhibited among animals in the following ways : 1. By a transfer of members from the locomotive to the cephalic scries. 2. By the anterior of the locomotis'e organs participating to some extent in ce- l)halic functions. • 3. By increased abbreviation, concenti'ation, compactness, and perfection of structure, in the parts and organs of the anterior portion of the body. 4. By increased abbreviation, condensation, and perfection of structure in the posterior, or gastric and caudal portion of the body. .'i. By an upward rise in the cephalic end of the nervous system. This rise reaches its extreme limit in Man." 10 THE CLASS OF INSECTS. iium each consist, in the embiyo, of two lateral parts, or halves, -which, during development, unite on the median line of the body. Typically, therefore, the crustacean ring consists pri- marily of eight pieces. The same number is found in all insects which are wingless, or in the larva and pu]m state ; this applies also to the Myriopods and Spiders. In the Myriopoda, or Centipedes, the broad tergum overlaps the small epiniera, while the sternum is much larger than in the Spiders and Insects. In this respect it is like the broad rtat under-surface of most worms. Hence the legs of the Centipede are inserted very far apart, and the "breast," or sternum, is not much smaller than the dorsal part of the crust. In the Jidus the dorsal piece (tergum) is greatly' developed over the sternum, but this is a departure from what is ap- parently the more typical form of the order, i. e. the Centipede. In the Spiders there is a still greater disproportion in size between the tergum and the sternum, though the latter is very large compared with that of Insects. The epimera and episterna, or side-pieces of the Spiders, are partially concealed by the over-arching tergum, and they are small, since the joints of the legs are very large, Audouin's law of development in Arthro- ])ods showing that ono part of the insect crust is .always developed at the expense of the adjoining part. In the Spider we notice that the back of the thorax is a single solid plate consisting originally of four rings consolidated into a single hard piece. In like manner the broad solid sternal plate results from the reunion of the same number of sternites cor- responding, originally, to the number of thoracic legs. Thus the whole upper side of tlie head and thorax of the Spider is consolidated into a single hard horny immovable plate, like the upper solid pai't of the eephalothorax of the Crab or Shrimp, Hence the motions of the Spiders are very stiff com- pared with those of many Insects, and correspond to those of the Crab. The crust of the winged insect is modified for the per- formance of more complex motions. It is subdivided in so different a manner from the two lower orders of the class, that it would almost seem to have nothing in common, structurally speaking, with the groups below them. It is onh' by examin- COMPOSITfON OF THE IXSECT-CIIUST. 11 ing the lowest windless forms such as the Louse, Flea, I'odura, and Bark-lice, where we see a transition to the Or- ders of Spiders and Myriopods, that we can perceive the plan pervading all these forms, uniting them into a common class. A segment of a winged six-footed insect (Hexapod) consists typically of eight pieces which we will now examine more leisurel3^ Figure 12 represents a side-view of prm the thorax of the Telea Polyphemus, or Silk- pt- worm moth, with the legs and wings removed. Each ring consists primarily of the tergum, the two side-pieces (epimerum and episternum) and the stei'num, or breast-plate. But one of these pieces (sternum) remains simple, as in the lower orders. Tlie tergum is divided into four pieces. They were named by Au- douin going from before backwards, Fig, 12. the prcescutum, scutum, scutellum, and postscutelhim. The scutum is invariably present ;ind forms the larger part of the w upper portion (tergum) of the tho- <'pm"' rnx ; the scutellum is, as its name indicates, the little shield so promi- nent in the beetle, which is also uniformly present. The other two pieces are usually minute and crowded down out of sight, and placed between the two oppos- ing rings. As seen in Fig. 11, the praescutum of the moth is a small rounded piece, bent vertically down, so as not to be seen from above. In the lowly organized Hepiahis, and some Fig. 11. Tergal view of the middle searment of the thorax of Telea Polyphemus, prm, pr.'csctitum ; ins, .scutum; xcm, scutellum; ptm, postscutellum; j^<, patagium, or shoulder tippet, covering the insertion of tho wings. — Oryiinal. Fig. 12. Side view of the thorax of T. Poti/phemiis, the liairs removed. 1, Pro- tliorax ; 2, Mesothorax ; :i, Metathorax, separated by the wider black lines. Tergum of the prothorax not represented, ms, mesoscutum : sciu, mesoscutellum; ms" , mctascutum ; scm", metasciitellum ; pt, a supplementary piece near the inser- tion of patagia ; «•, pieces situated at the insertion of the wings and surrounded by nu-mbrane; em, epimerum of prothorax, the long upright piece above being the episternum; eprti', episternum of the mesothorax; em", epimerum of the same; cpm", episternum of the metathorax; en", epimerum of the same, divided into two pieces; c, c", c", coxa;; te', !e', le", trochantines; tr, tr, tr, trochanters. — Original. epm tr te ■ tr c" tr 1 2 3 12 THE CLASS OF INSECTS. Neuroptera, such as the Polystoechotes (Fig. 13a), the prffi- scntum is hirgs, well developed, triangular, and wedged in between the two halves of the scutum. The little piece succeeding the scutellum, i.e. the postscu- telhun, is still smaller, and rarely used in descrip- tive entomology. Thus far we have spoken of the 3j middle, or mesothoracic, ring, where these four pieces are most equally developed. In the first, "^' or prothoracic, ring, one part, most probably the scutum, is well developed, while the others are aborted, and it is next to impossible to trace them in most insects. The prothorax in the higher in- sects, such as the Hymenoptera, Lepidoptera, and Diptera is very small, and often intimately soldered to the succeeding or mesothoracic ring. In the lower insects, however, such as the Coleoptera, the bugs (Hemiptera), grasshoppers and their allies (Orthoptera), and the Neuroptera, the large broad pro- thorax consists almost entirely of this single piece, and most M-riters speak of this part under the name of "thorax," since the two posterior segments are concealed by the wings when the animal is at rest. The metathorax is usually very broad and short. Here we see the scutum split asunder, with the praescutum and scutellum wedged in between, while the post- scutelluni is aborted. On the side are two pieces, the upper (epimerum) placed just beneath the tergum, which is the collective name for the four tergal, or dorsal, pieces enumerated above. In front of the epimerum and resting upon the sternum, as its name im- plies, is the episternum. These two parts (pleurites) compose the flanks of the elemental ring. To them the legs are articu- lated. Between the two episterna is situated the breast-piece (sternum), which shows a tendency to grow smaller as we ascend from the Neuroptera to the Bees. In those insects provided with wings, the epimera are also subdivided. The smaller pieces, hinging upon each other, as it were, give play to the very numerous muscles of flight Fig. 13. A tergal view of thorax of Hepialus {Sthenojns) ; 1, prothorax ; 2, nieso- thorax; 3, metathorax. The prothorax is very small compared witli that of Poly- stte.chotes (13 «, 1), where it is nearly as long as broad.— Origimd. COMPOSITION OF THE INSECT-CRUST. 13 needed by the insect to perform its complicated motions wliile on the wing. The insertion of tlie fore wing is concealed by the "shoulder tippets," or patagia (Fig. 11), which are only present in the mesothorax. The external opening of the spiracles just under the Aving perforates a little piece called by Audouin the j;er/- treme. A glance at Figures 11 and 12 sliows how compactly the various parts of the thorax are agglutinated into a globular mass, and that this is due to the diminished size of the first and third rings, while the middle ring is greatly enlarged to support the muscles of flight. There are four tergal, four pleural, two on each side (and these in the H3^menoptera, Lepi- doptera, and Diptera subdivide into several pieces), and a single sternal piece, making nine for each ring and twenty- seven for the whole thorax, with eight accessory pieces (the three pairs of peritremes and the tvfo ptatagia)^ making a total of thirty-five for the entire thorax ; or, multiplying the four tergal pieces by two, since they are formed by the union of two primitive pieces on the median line of the body, we have thirty-nine pieces composing the thorax. Table of the Parts ok the Thorax applied to the Pro-, Meso-, and Metathorax, respectively. , PrfBscutum, r Dorsal S Scutum, I Surface i ScutoUum. ^ Postscutellum. Thorax <[ Pleural ^ Epislernura, I ^^^ t Epistenial apophysis, Stigma, Peritrerae. I f «™'^1 \ Sternum. 1^ Surface i We must remember that these pieces are rarely of precisel\' the same form in any two species, and that they differ, often in a very marked wa}', in different genera of insects. How sim pie, then, is the typical ring, and how complex are the va- rious subdivisions of that ring as seen in the actual, living insect, where each part has its appropriate muscles, nerves, and trachejB ! We have seen how the thorax is formed in Insects generally, let us now advert to the two types of thorax in the six-footed 14 THE CLASS OF INSECTS. insects. In the higher series of orders, comprising the dip- tera, Lepidoptera and Ilymenoptera, placing the highest last, the thorax shows a tendency to assume a globular shape ; the upper side, or tergum, is much arched, the pleural region bulges out full and round, while the legs conceal at their insertion the sternum which is minute in size. In the lower series, emV)racing the Coleoptera, Ilemiptera, Orthoptera, and Neuroptera, the entire body tends to be more flattened ; in the thorax the tergum is broad, especially that of the prothorax, while the pleurites (episterna and epimera) are short and bulge out less than in the higher series, and the ster- num is almost invariably well developed, often presenting a large thick breast-plate bearing a stout spine or thick tubercle, as in (Edipocla. We can use these characters, in classifying insects into orders, as tliey are common to the whole subchiss. Hence the use of characters drawn from the wings and mouth- parts (which are sometimes wanting), leads to artificial dis- tinctions, as they are jyeripheral organs, though often convenient in our first attempts at classitying and limiting natural groups. The abdomen. In the hind body, or third region of the trunk, the thi'ee divisions of the typical ring (artlnomere), are entire, the tergum is broad and often not much greater in ex- tent than the sternum ; and the pleurites also form either a single piece, or, divided into an epimerum and episternum. form a distinct lateral region, on which the stigmata are sit- uated. The segments of tlie abdomen have received from Lacaze-Duthiers a still more special name, that of urite^ and the different tergal pieces belonging to the several rings, but especially those that have been modified to form the genital armor have been designated by him as tergltes. We have applied this last term to the tergal pieces generally. The typi- cal number of abdominal segments is eleven. In the lowest insects, the Neuroptera, there are usually eleven ; as we have counted them in the abdomen of the embryo of Diplax. In others, such as the Hymenoptera and Lepidoptera, there may never be more than ten, so far as present observation teaches us. The formation of the sting, and of the male intromittent organ, may be observed in the full-grown larva and in the in- COMPOSITION OF THE OVIPOSITOR. 15 (tomplete pupa of the Humble-bee, and other thin-skiunod Ilymenopterous larvae, and in a less satisfactory way in the young Dragon-flies. If the larva of the Humble-bee be taken just after it has become full-fed, and as it is about to enter upon the pupa state, the elements O ° O <:=3!c:^ {sterno - rhab- dites Lacaze- Duthiers), or tubercles, destined to Fig. ic. form the ovipositor, lie in separate pairs, in two groups. Fig. 14. Fig. 15. exposed distinctly to view, as in Figures 14-18. The ovipositor thus consists of tliree pairs of slender non-articulated tubercles, situated in juxta- position on each side of the mesial line of the body. The first pair arises from the eighth abdominal ring, and the second and third pair grow out from the ninth ring. The ends of the first pair scarcely reach beyond the base of the third pair. With the growth of the semi-pupa, the end of the abdomen decreases in size, and is Fig. is Fig. 14. Rudiments of the sting, or ovipositor, of the Humble-bee. 8, 9, 10, stevnites of eighth, ninth, and tentli abdominal rings in the larva, a, ijrst pair, situ- ated on the eighth sternite; 6, second and inner pair; and c, the outer pair. The let- tering is the same in figures 14-2'2. The inner pair (6), forms the true ovipositor, through which the eggs are supposed to pass when laid by the insect, the two outer pairs, a and c, sheathing the inner pair. Ganin shows that in the embryo oi' /'oli/iiem:i,{Vig.G.'y5), the three pairs of tubercles arise from the 7th, 8th and 9th seg- ments respectively. Fig. 15, 1G. The same a little farther advanced. Fig. 17. The three pairs now appear as if together growing from the base of the ninth segment: 17a, side view of the same, showing the end of the abdomen grow- lug smaller through the diminution in size of the under side of the bod)'. Fig. 18. The three pairs of rhabdites now nearly equal in size, and nearly ready to unite and form a tube; ISa, side view of the same; the end of tlie abdo- men still more pointed ; the ovipositor is situated between the seventh and tenth rings, and is partially retracted within the body. 16 THE CLASS OF INSECTS. gradually incurved toward the base (Fig. 18), and the three pairs of rhabdites approach eacli other so closely that the two outer ones completely ensheath the inner, until a complete extensible tube is formed, which is gradually withdrawn entirely within the body. The male genital organ is originally composed of three pairs (two pairs, apparently, in ^s- chna, Fig. 19) of tubercles all arising from the ninth abdominal ring, being sternal outgrowths and placed on each side of the r~TT%-~\ mesial line of the body, two be- v_iy_y ing anterior, and very unequal in size, and the Fig. 19. third pair nearer the base of the abdomen. The ex- ternal genital organs are to be considered | as probably homologous with the limbs, as Ganin has shown that they bud out in the same manner from (see p. 704 fig. 655) tlie arthromere* '* Tiiis view will apply to the Fig. 21. genital armor of all Insects, so far as we have been able to observe. It is so in the pupa of ^schna (Fig. 21), and the pupa of Agrion (Fig. 22), which com- pletely repeats, in its essential features, the structure of the ovipositor of Bombus. Thus in ^schna and Agrion the ovipositor consists of a pair of closely appressed ensi- form processes which grow out from under the posterior edge of tlie eighth abdominal ring, and are embraced between two pairs *This term is proposed as better defining the ideal ring, or primary zoological element of an articulated animal than the terms somite or zodnite, which seem too vague; we also propose the term arthroderm for the outer crust, or body walls, of Articulates, and artliropleura for the j)leural, or limb-bearing region, of the body, bemgthat portion of the arthromere situated between the tergite and sternite. Fio. 19. The rudiments of the male intromittent organ of the pupa of iKschna, consisting of two flattened tubercles situated on the ninth ring; the outer pair large and rounded inclosiug the smaller linear oval pair. Fig. 20. The same in the Humble-bee, but consisting of three pairs of tubercles, X, II, z ; 8, 9, 10, the last three segments of the abdomen. Fig. 21. The rudimentary ovipositor of the pupa of ^^schna, a Dragon-fly. Fig. 22. The same in pupa of Agrion, a small Dragon-fly. Here the rudiments of the eleventh abdominal ring are seen, d, the base of one of the abdominal false gills. The ovipositor of Cicada is formed in the same -w ay. — Figs, li-22 original. COMPOSITION OF THE OVIPOSITOK. 17 of thin lamelliform pieces of similar form and structure, ansiiig tVom the sternite of the ninth ring. These outgrowths appar- ently also homologize with the filiform, antennse-like, jointed appendages of the eleventh ring, as seen in the Perlidae and most Neuroptera and Orthoptera (especially in Mantis tes- sellata where they (Fig. 23) closely resemble antennae), which, arising as they do from the arthropleural, or limb- bearing region of the body, i. e. between Fig. 23. the sternum and episternum, are strictly homologous with the abdominal legs of the Myriapoda, the "false legs" of cater- pillars, and the abdominal legs of some Neuropterous larvae {Corydalis, Phryganeidce, etc.). It will thus be seen that the attenuated form of the tip is produced by the decrease in size of certain jDarts, the actual disappearance of others, and the perfection of those parts to be of future use. Thus tow^ai-ds the extremity of the body the pleurites are absorbed and disappear, the tergites overlap on the sternites, and the latter diminish in size and are withdrawn within the body, while the last, or eleventh sternite, entirely disappears.* Meanwhile the sting gi-ows larger and larger, until finally we have the neatly fashioned abdominal tip of the bee concealing the complex sting with its intricate system of visceral ves- sels and glands. The ovipositor, or sting, of all insects, therefore, is formed on a common plan (Fig, 24). The solid elements of the arthro- Fig. 24. *In Ranatra, however, Lacazo-Duthiers has noticed the envious fact that in order to Ibrm the long respiratory tube of this insect, the tergite and sternite of the l>rcgeuital (eighth) segment are aborted, while the pleurites are enormously en- larged and elongated, so as to carry the stigmata far out to the end of the long tube thus formed. Fig. 23. End of the abdomen of Mantis tesxellatn ; p, many-jointed anal stylo resembling an antenna. 5-11, the last seven abdominal segments;, the S-llth ster- uitcs being obsolete. — i-Yoj^i Lncnze-Duihiers. Fig. 24. Ideal plan of the structure of the ovipositor m the adult insect, i-'t, the tergites, connected by dotted lines with their corresponding sternites. b, the eighth tergite, or anal scale; c, epimerum ; n', a, two pieces fomiing the outer pair of rhabditcs; i, the second pair, or stylets; and /VUio inner pair,.or. stjug; d, Uie 18 THE CLASS OF INSECTS. mere are modified to form the parts supporting the sting alone. The external opening of the oviduct is always situated between the eighth and ninth segments, while the anal opening lies at the end of the eleventh ring. So that there are really, as Lacaze-Duthiers observes, three segments interposed between the genital and anal openings. The various modifications of the ovipositor and male organ will be noticed under the diftferent suborders. The Structure of the Head. After studying the com- position of the thorax and abdomen, where the constituent parts of the elemental ring occur in their greatest simplicity, we may attempt to unravel the intricate structure of the head. We are to determine whether it is composed of one, or more, segments, and if several, to ascertain how many, and then to learn what parts of the typical arthromere are most largely developed as compared with the development of similar parts in the thorax or abdomen. In this, perhaps the most difficult problem the entomologist has to deal with, the study of the head of the adult insect alone is only guesswork. We must trace its growth in the embryo. Though many writers consider the head as consisting of but a single segment, the most emi- nent entomologists have agreed that the head of insects is com- posed of two or more segments. Savigny led the way to these discoveries in transcendental entomology by stating that the appendages of the head are but modified limbs, and homol- ogous with the legs. This view at once gave a clue to the complicated structure of the head. If the antenna and biting organs are modified limbs, then there must be an elemental segment present in some form, however slightly developed in the mature insect, to which such limbs are attached. But the best observers have differed as to the supposed number of such theoretical segments. Burmeister believed that there were two only ; Carus and Audouin thought there were three ; McLeay and Newman four, and Straus-Durckheim recognized seven. From the study of the semipupa of the Humble-bee (Bombus) support of the sting; e, the sxipport of the stylet (t). if, the anus ; O, the outlet of the oviduct. The seventh, eighth, and ninth sternites are aborted. — From Lacazt- Duthiers. THE STRUCTURE OF THE IIKAO. 19 and several low Ncuropterous forms, as the larva of Ephemera^ but chiefly the embryos of Dljplax^ Chrysopa^ Attelabus, Neina- tus, and Pulex, we have concluded that there are four such ele- mental segments in the head of hexapodous insects. On reference to fig. 57 it will be seen that there is a sternal portion on the nnder side of the two posterior segments of the head, and in the embryo of Attelabus we have seen sterna also developed in the antennal and mandibular segments, so that we may conclude that there are four segments in the head of all SIX footed insects, corresponding to the jointed appendages, I. e. the labium, or second maxilhie, the first maxilU^e, the man- dibles, and the antennae. Though having, in accordance with the generally received opinions of Milne-Edwards, Dana, and others, believed that the eyes of Crustacea, and therefore of Insects, were the homologues of the limbs, and developed on separate segments placed in front of the antennal segment, as stated in the previous editions of this work ; I have, however, on farther study of the subject, been led to reconsider the mat- ter, and decide that the eyes are but modified dermal sense cells, and in certain articulates developed on limb-bearing seg- ments. Thus in tlie King Crab {Limulus) a pair of ocelli are situated on the first segment of the body, and the large com- pound eyes grow out on the back of the third segment, both bearing limbs. In the embryos of all the insects yet exam- ined, the eyes are groups of specialized cells of the skin which grow out on the upper, or tergal, side of the same segment which bears the antennae. In certain mites, as Ilydrachna, and its allies, tlie simple eyes are situated over the second pair of legs, and at a considerable distance behind the head. Among the worms, also, organs of sight, as in Polyophthalrmis, arc developed on each segment of the Ijod}' ; or, as in certain Pla- narians, scattered irregularly over the body. The three ocelli, when present, are developed after tlie eyes appear. Each of these three ocelli is situated upon a distinct Jiece ; but we must consider the anterior single ocellus as in reality formed of two, since in tlie immature pupa of Bombus the anterior ocellus is transversely ovate, resulting from the fusion of two originally distinct ocelli. Thez'C are, therefore, apparentl}' two pairs of ocelli. The clypeus and labrum are 20 THE CLASS OF INSECTS. simply a fold of the skin of the front part of the antennary segment, and are not to be compared with the tergite or rudi- ment of the eleventh segment of tlie abdomen. Now, since the arthropleural is the limb-bearing region in the thorax, it must follow that this region is quite well devel- oped in the head, while the tergal region, bearing the organs of sio-ht, sometimes of enormous size, is perhaps still more largely developed ; and as all the parts of the head are subordinated in their development to that of the appendages of which they form the support, it must follow logically that the larger por- tion of the body of the head is pZe»?'a? and tergal, and that the sternal parts are A'ery slightly developed. Thus each region of the body is characterized by the relative development of the three parts of the arthromere. In the abdomen the upper (tergal) and under (sternal) surfaces are most equally devel- oped, while the pleural line is reduced to a minimum. In the thorax the pleural region is much more developed, either quite as much, or often more than the upper, or tergal portion, while the sternal is reduced to a minimum. In the head the pleurites form the main bulk of the region, and the sternites are reduced to a minimum. Table of the Segments of the Head and their Appendages, beginning with the most antekiok. First Se Pleural (genu), ) Sternal (gula), Antennae, together with the labrum, epipharynx, clypeus, eyes, and ocelli. Mandibles. First maxillae. Second maxillae (Labium). The Apjyendages. We naturally begin with tlie thoracic appendages, or legs, of which there is a pair to each ring. The leg (Fig. 25) consists of six joints, the basal one, the coxa, in the Hyineuoptera, Lepidoptera, and Diptera, consisting of two THE APPENDAGES. 21 pieces, i.e. the coxa and trocliantine (see Fig. 12); the tro- vlianter ; the femur ; the tibia, and, kistly, tlie tarsu.s, which is subdivided into from one to five joints, the latter being qa the normal number. The terminal joint ends in a pair ^ of claws between which is a cushion-like sucker called J/d the pulvillus. This sucking disk enables the Fly to walk upside down and on glass. In the larva, the feet are short and horny, and the Fig. 2.5. joints can be still distinguished. In Myriopods, each segment of the abdomen has a pair of feet like the thoracic ones. We must consider the three pairs of spinnerets of Spiders, which are one to three-jointed, as homologous with the jointed limbs of the higher insects. In the six-footed insects (Hexapoda), the abdominal legs are deciduous, being present in the Coleopterous grub, the Dipterous maggot, the caterpillar, and larva of the Saw-fly, but disappearing in the pupa state. They are often, as in most maggots, either absent, or reduced in number to the two anal, or terminal pair of legs ; while in the Saw-flies, there are as many as eight pairs. These "false" or "prop-legs" are soft and fleshy, and without articulations. At the retrac- tile extremity is a crown of hooks, as seen in caterpillars or the hind-legs of the larva of Chironomns (Fig. 26), in which the prothoracic pair of legs is reduced to inarticu- late fleshy legs like the abdominal ones. The position of the different pairs of legs x;-^'^ '^?i deserves notice in connection witli the i)rinciple of " antero-posterior symmetry." The fore- legs are directed forwards like the human arms, ^ 's- 26. but the two hinder pairs are directed backwards. In the Spiders, three pairs of abdominal legs (spinnerets) are retained through- out life ; in the lower Hexapods, a single pair, which is ap- pended to the eleventh segment, is often retained, but under a form which is rather like an antenna, than limb-like. lu some Neuropterous larva? (Phryganea^ Corydalus, etc.) the anal pair of limbs are very well marked : they constitute the " anal forceps " of the adult insect. They sometimes become true, many-jointed appendages, and are tlien remarkably like Fig. 25. A, coxa; B, trochanter; C, femur; 1), tibia: F, tibial spurs ; E, tarsus. divided into five tarsal joints, the fifth ending in a claw. — From Sanborn. 22 THE CLASS OF INSECTS. nntennse, as iii Iho instance of Mantis tesseUata described by Jjacaze-Duthicrs (Fig. 23). In the Cockroach these append- ages, sometimes called "anal cerci," resemble the antennae of the same insect. In the Lepidoptera and Ilymenoptera they do not appear to be jointed, and are greatly aborted. The Wings. The wings of insects fh'st appear as little soft vascular sacs permeated by trachea?. The}- grow out in the preparatory stages (Fig. 27) of the pupa from the side of tlie i- thorax and above the insertion of the legs, i.e. between the epimerum and f,."« tergum. During the pupa state they are iiad-like, but when the |)upa skin is thrown otf they expand with air, and in a few minutes, as in the Butterfly, enlarge to many times their original size. The wings of insects, then, are simple expansions of the crust, spread over a framework of horn^'^ tubes. These tubes are really double, consist- ing of a central trachea, or air tube, '°' " ■ inclosed within a larger tube filled with blood, and which performs the functions of the veins. Hence the aeration of the blood is carried on in the wings, and thus they serve the double purpose of lungs and organs of flight. The number and situation of these veins and their branches (veinlets) are of great use in separating genera and species. The t3'pical number of primary veins is five. They diverge outward at a slight angle from the insertion of the wing, and are soon divided into veinlets, from which cross veins are tlu'own out connecting with others to form a net-work of veins and veinlets, called the venation of the wing (Figs. 28, 29). The interspaces between the veins and veinlets are called cells. At a casual glance the venation seems very irregular, but in many insects is simi)le enough to enable us to trace and name the veinlets. The five main veins, most usually present, are Fig. 27. The scmiijupa of Bombns, the larva skin having been removed, show- ing the two iiairs of rudim'ntary wings growing out from the mcsothorax (/j), ancj metathorax (?;i). "■ a»d the seven succeeding dots represent the eight abdominal stigmata, the first one (n) being in the pupa situated on the thorax, since the first ring of the abdomen is in this stage joined to the thorax. — Original. THE WINGS. 23 Fig. 2S. called, beginuing at the costa, or front edge, the costal, subcostal, median, sxihmedian, and internal, and sometimes the median divides into two, making six veins. The costal vein is un- divided ; the subcostal and me- dian are divided into several branches, while the submedian and internal are usually simjjle. The venation of the fore- wings affords excellent marks in separating genera, but that of the hind wings varies less, and is consequently of less use. The wings of many insects are divided by the veins into three Avell-marked areas ; the costal, median, and internal. The costal area (Fig. 316) forms the front edge of the wing and is the strongest, since the veins are nearer together than elsewhere, and thus afford the greatest resistance to the air p-i^ 29. Fig. 28. ForeandhindwingsofaButterfly, showing the venation. I. forewing: a, costal vein; 6, subcostal vein; 61, 62, 63, 64, 65, five subcostal veinlets ; o, inde- pendent vein (it is sometimes a branch of the subcostal, and sometimes of the me- dian vein) ; d, median vein ; rfi, d2, (^3, d4, four median veinlets ; e, submedian vein ; /, internal vein; h, mterno-median veinlet (rarely found, according to Doubleday. except in Papilio and Morpho); 6 and rf are situated m the "disc.al cell ;•' r/i, i/2, ,7.% the upper, middle, and lower discal veinlets. In the Bombycida; and many other moths £^1 and ff-2 are thrown off from the subcostal and median veins respectively, meeting in the middle of the cell at (/2. They are sometimes wholly absent. II. The hind wing; the lettering and names of the veins and veinlets the same as in the fore wmg. — Slic/hthj clianrjed from Doubledrnj. Fig. 29. Forewing of a Hymenopterous insect, c, costal vein; sc, subcostal vein, m, median vein; sm, submedian vein; i, internal vein; c, 1,2,3, the first, second, and third costal cells; the second frequently opaque and then called the pterostigma. sc, 1, 2, 3, 4, the four subcostal cells ; m, 1, 2, 3, 4, the median cells ; sm, 1, 2, 3, the three submedian cells ; ii, the internal cell ; this is sometimes divided into two cells, and the number of all but the costal cells is inconstant, the outer row of cells (4, 4, 3) being the first to disappear. The costal cdr/e extends from c to c ; the outer c, the apex ; the onter edge extend:; ft-om the apex (c) to a, and the inner edge extends from a, the inner angle, to the insertion of the wing at i— Original. Figs. 30-32 /rom Scudder. 24 THE CLASS OF INSECTS. Fig. 31. (lining flight. The median area (Fig. 31 a) is the largest. It is in the grasshopjiers and crickets sometimes modified to form a musical organ, being drum-like, as in the GucantlLus (Fig. 30), or rasp-like, as in Arcliyp- tera (Fig. 31a). The internal area (c) is the smallest, and less dis- tinctly marked than the two other regions ; the musical tile-like or- gan of Phayieroptera curvicauda, a grass- hopper (Fig. 32 d) is situated on this area. The limits of the edges of the wing vary in almost every genus, and their comparative length affords (excellent generic characters. The front edge (Fig. 29) is called the costal, its termina- tion in the outer angle of the wing is called the apex; the outer edge is situated between the apex and the inner an- gle, between which and the base of the wing is the inner, or internal, edge. These distinc- tions are of most use in describing the butter- flies and moths. The A]ii)endages of Fiy. 31a. the Head. These organs are divided into two groups, the first of which comprise the sensory organs, i. e. the ocelli, eyes, and antenna;, which are attached to the region in front of the mouth, or preoral region of the head. The second group consists of the sensorio-digestive appendages, combining the power of finding and seizing the food and preparing it fof digestion. They are inserted behind the mouth and belong to the postoral region of the head. THE APPENDAGES OF THE HEAD. 25 We will first describe the ocelli, which are theoreticjilly the most anterior organs of the head, ending with the basal appen- dages, the labium (second maxiUas) being the hindermost. The simple eye, Ocellus, or Stemma, is the simplest form of the eye. Its most elementary form (seen in the larva of the Bot-fly and the Cecidomyian larva of 3fiastor) is that of a brown spot, or group of pigment-cells lodged under the skin and against which a nerve-filament impinges. Over this spot New- port states that the tegument is transparent and convex, resembling a true cornea, or eye-lens. A well-developed ocellus consists, according to Newport, of a "very convex, smooth, single cornea, beneath which is a spherical crystalline lens, resting upon the plano-convex surface of the expanded vitreous humor, the analogue of the transparent cones of the compound eyes." Miiller believes that the function of the ocelli is the perception of nearer objects, while that of the compound eyes is to see more distant objects. The ocelli constitute the only visual organs in the Myriapods (except Cermatia), the Arachnida, and the larvae of many Six-footed Insects ; they are usually from one to six on a side. In adult insects they are generally three in number, and are generally present except in the large majority of Coleoptera. Then- normal site is in front of the eyes, but they are usually thrown back, during the growth of the insect, behind the eyes, on the vertex, or topmost part of the head (Fig. 33). The Compound Eyes are a congeries of simple eyes. During the growth of the insect the simple eyes of the larva increase j^lH in number, and finall}'^ coalesce to form the compound Mp/ eye, or compound cornea, the surface of which is Fig. 34. very convex and protuberant in the predaceous insects, or those requiring an extended field of vision. The number of facets, or cornese, vary from fifty (in the Ant) to 3,650, the latter number being counted by Geoffroy in the eye of a Butterfl3\ These facets are usually hexagonal, as in the Dragon-fly (Fig. 34), or, rarely, quadrangular. Fig. 33. Ocelli of three species of Sand-wasps, PompUus. — From Cresson. Fig. 34. Three hexagonal facets of the compound eye of a fossil Dragon-fly, greatly magnifled. — i^Vom Dawson. 26 THE CLASS OF INSECTS. The Antennce (Figs. 35, 36) are inserted usually in the adult insect between, or in front of the eyes, though in the embryo they arc inserted below and in front of the eyes. It is normally a long, filiform, slender, many- jointed appendage, undergoing great changes in form. When it is highly specialized, as in Coleoptera and Hymenoptera, it is divided into three parts, the basal or scajoe^ the middle or j^eclicel, and the terminal part or Jiagellum, ^'S- ^c- Fig. 35. or davola, which usually comprises the greater part of the antenna. It is believed by some that the sense of hearing is lodged in the antennae, though Siebold has discovered an auditory apparatus situated at the base of the abdomen of some, and in the fore-legs of other species of Grasshoppers. Mr. J. B. Hicks has made the latest studies on the auditors- apparatus. According to him "it consists first of a cell, sac, or cavity filled with fluid, closed in from the air by a mem- brane analogous to that which closes the foramen ovale in the higher animals ; second, that this membrane is, for the most part, thin and delicate, but often projects above the surface, in either a hemispherical, conical, or canoe-shaped, or even hair- like form, or variously marked ; thirdly, that the antennal nerve gives off branches which come in contact with the inner wall of the sacs ; but whether the nerve enters, or, as is most probable, ends in the small internally projecting papilla which I have shown to exist in many of these sacs, it is very difficult to say. Tlie principal part of the nerve proceeds to these organs, the remaining portion passing to the muscles, and to the roots of the hairs, at least to those of the larger sort." On the other hand, Lefebvre, Leydig, and Gerstaecker regard this so-called "auditory apparatus" as an organ of smell. The antenniB have also the sense of touch, as may readily be observed in Ants, Bees, and the Grasshopper and Cockroach. "The Honey-bee, when constructing its cells, ascertains their proper direction and size by means of the extremities of these Fig. 35. Filiform antenna of Amphizoa. — From Horn. Fig. 36. A, lamellate antenna of a Lamellicorn Beetle; B, antenna of a Fly, with the bristle thrown off from the terminal joint; C, bristle-like antenna of a J.)ragon-fly, Libdlula. — From Sanborn. THE APPENDAGES OF THE HEAD. 27 organs ; while the same insect, when evidently affected by sounds, keeps them motionless in one direction, as if in the act of listening." (Newport.) After cutting off one or both antennae of the June beetle, Ladmosterna, the insect loses its power of directing its flight or steps, wheeling about in a senseless manner. Dr. Clemens observed that the Cecropia moth was similarly affected after losing its antennae. The Mandibles (Fig. 37) are inserted on each side of the mouth-opening. They usually consist of but a single joint, H Fig. 37. representing probably the basal part of the ideal limb. This part, however, is often subdivided by two longitudinal furrows into three parts, each ending in a "tooth" of unequal size for tearing and cutting the food. This tripartite form of the man- dibles, to which attention has been called by Mr. Scudder, is more fully carried out in the maxilla, where each portion is highly specialized. The mandibles vary gi-eatly in form and size. The two cutting edges are usually opposed to each other, or frequently overlap in the carnivorous forms. Their base is often concealed by the clypeus and labrum. Their motion is transverse, being the reverse of the motion of the jaws of Ver- tebrates. a Fig. 38. b The Maxillce (Figs. S8b, '39) are much more complicated organs than the mandibles. They are Fig. 37. Different forms of mandibles. A, mandible of Cicindda purpurea; B. Phylloptera, ii green grasshopper; C, Libellula trimaculata; D, [^espa maculat a, or jiaper-making Wasp ; E, " rostrum " or jointed sucker of the Bed-bug, Cimex lectu- larius, consisting of mandibles, maxillre, and labium; F, proboscis, or sucker, of a Mosquito, Culex, in which the mandibles are long and bristle-like. — From Sanborn. G, mandible of Amphizoa; H, mandible of ^craiws, a genus of Cockchafers. — From Horn. Fig. 38. a, mentnm and labial palpi; b, one ma.villa, with its palpus, of Acra- tus. — From Horn. Fig. 31). Maxilla of Amphizoa, with the two lobes (stipes and lacinia), and the palplfer bearing the four-jointed palpus. — From Horn. 28 THE CLASS OF INSECTS. inserted cu the under side of the head and just behind the mouth. The maxilla consists of a basal joint, or cardu^ beyond which it is subdivided into three lobes, the stijjes, or footstalk ; the ^mlpifer^ or palpns-bearer ; and the lacinia, or blade. The stipes forms the outer and main division of the organ. The lacinia is more membranaceous than the other l)arts, and its upper surface is covered with fine hairs, and forms a great part of the side of the mouth. It is divided into two lobes, the superior of which is called the galea, or helmet, Vhich is often a thick double-jointed organ edged with stiff hairs, and is used as a palpus in the Orthoptera and many C'oleoptera. The inferior lobe is attached to the internal angle of the lacinia. It terminates in a stiff minute claw, and is densely covered with stout hairs. The maxillary palpi are long, slender, one to four-jointed organs. In Perla I have found that both pairs of palpi bear organs probably of smell. The maxillae vary greatly in the different groups. Their office is to seize the food and retain it within the mouth, and also to aid the mandibles in comminuting it before it is swallowed. This function reminds us of that of the tongue of vertebrate animals. The labium, or second maxillce (Fig. 40), is placed in front of the gtda, which forms the under part of the head, and is bounded a on each side by the gence, or cheeks, and posteriorly by the occiput. The genaj are bounded laterally by the epicranium and the under side of the eyes. In front are Fig. 40. situated the basal parts of the labium, or second maxillae, which embraces the submentum and mentina (or labium proper). The labial palpi are inserted into the mentum, but often the latter piece is diflerentiated into two, the anterior of which takes the name of palp)iger, called hy Dr. Leconte (Smithsonian Miscellaneous Collections) the ligula, and from which the palpi originate. The ligula is the front edge of the labium, being the piece forming the under lip. It is often a fleshy organ, its inner surface being continuous Fig. 40. Ligula and labial palpi of ^m;)/iiso(7, an aquatic beetle. It is quadrate and without paraglossje ; a, mentum of the same, being deeply incised, and with a tooth at the bottom of the excavation. — From Horn. THE APPENDAGES OF THE HEAD. 29 with the soft membrane of the mouth. In the Bees, it is enor- mously developed and covered with soft hairs. It is often confounded with the palpiger. In Hydrous it is divided into two lobes. In most of the Caruhidce and Bees it is divided into three lobes, the two outer ones forming the paraglosm: (P'ig. 41 ?)i), and acting as feelers, while the middle, usually much longer, forms the lingua^ or tongue, being the continuation of the ligula. In the bees, where the ligula is greatly developed, it performs the part of the tongue in Vertebrates, and aids the max- illae in collecting nectar and pollen. The roof of the mouth is formed by the labrum and the epipharynx (Fig. 42 c), a small fleshy tubercle concealed beneatli the labrum. It is seen in the bees on turning up the labrum. It probably corresponds to the "labellum" of Schiodte. The labrum (Fig. 41 e) is usually transverse and situated in front of the clypeus (Fig. 416). The shield-like clypeus is the broad, ^'S- 4i- visor-like, square piece forming usually the front of the head. Behind it is the clypeiis posterior, or sujiva-dypeus^ a subdivision of the clj^Dcus, and especiall}- observable in the Ilymenoptera. The epicranium forms a large part of the head ; it is bounded posteriorly b}' the occiput, on the sides by the eyes, and in front by the clypeus, and though xisually described as a single piece, is really composed of several. The ocelli often appear to be situated upon it, though in reality they are placed upon a distinct piece or pieces. The "epicranial suture" is the line of junction of the two "procophalic lobes" (Huxley). Fig. 41. Front view of the head of a bee, Anihcphora. a, compornid eyes; r, three simple eye.s, situated niion the epicranium; ft, clyi>eiis; e, lal)nim ; d, an- tennje;/, inan(hl)k's: i, maxillio; /(, niaxiUnry palpi; /, palpifer; j, labial palpi; m, paraglossae; A;, ligula. — From Newport. so THE CLASS OF INSECTS. (These lobes will be explained farther on when speaking of their development in the embryo.) Behind the epicra- nium is the occiput, or base of the head. It belongs to the la- bial, or second max- illary segment, and helps to form a com- plete ring, articulat- ing with the thorax. It is perforated by a foramen to afford a connection between the interior of the head and thorax. It is sometimes, as in many Coleoptera, Or- thoptera, and Hemip- tera, elongated be- hind and constricted, thus forming a "neck." It will be seen beyond, that the labrum and clypeus are in the embryo dcAcloped from a '•tongue-like process whose inferior part eventually becomes the labrum, while superiorly it sends a triangular process (the rudiment of the clypeus) into the interval between the proce- phalic lobes." * This part {i. e. the clypeus and labrum) is the most anterior part of the head, and in the embryo, as in the adult, is normally situated in front of the ocelli, but is not to be compared with the " anal plate," or eleventh tergite, of the larva, or with the telson of the scorpion, as Huxley f supposes. Fig. 42. Side view of the front part of the head, together with the niouth- )>avt8 of the Humble-bee (Bombus). a, clypeus covered with hairs; 6, labrum: c, the fleshy cpipharyux i)artially concealed by the base of the mandibles {70, Translation) that on watching insects that move slowly he has distinctly perceived that three legs are always moved at one time, being advanced and put to the ground while the other three propel the body forwards. In perfect insects, those moved simultaneously are the fore and hind feet on one side, and the intermediate foot on the opposite ; and afterwards the fore and hind feet on that side, and the middle one on tht; other, so that, he remarks, in two steps the whole of the legs are in motion. A similar uniformity of motion takes place in the larva, although the whole anterior part of the bodj'^ is elevated and carried forwards at regular distances, the steps of the insect being almost entirely i)erformed by tlie 'false,' or abdominal legs." ^'■Inflight the motions depend upon the mcso- and meta- thoracic segments conjointly, or entirely upon the former. The THE NEUVOUS SYSTEM. 33 sternal, episternal, and epimeral pieces, freely articulated together, correspond in function with the sternum, the ribs, and the clavicles of birds.* The thorax is expanded and con- tracted at each motion of the wings, as in birds and other ani- mals, and becomes fixed at each increased effort as a fulcrum or point of resistance upon which the great muscles of the wings are to act, thus identifying this part of the body in function as in structure with that of other ani- mals." (Newport.) The Nervous System. In its simplest form the nervous system consists of two longitudinal cords, each with a swelling (nerve-knot, or ganglion,) corresponding to each segment (Fig. 43). Tliis cord lies on the ventral side of the body, but in the head it passes upwards, sending a filament from each side to surround the oesoph- agus, f As in the Vertebrates, the nervous cord of insects is composed of two distinct columns of fibres placed one upon the other, column, which is nearest to the exterior of the body, is that in which the ganglia, or enlargements, are situated. The upper one, or that which is internal and nearest to the viscera, is entirely without ganglia, and passes directly over the ganglia of the under column without forming part of them, but in vei\y * Bennet on tlie Anatomy of the Thorax in Insects, and its Fnuction during Flight. Zoological Journal, vol. i, p. 394. fThe brain of insects is formed of several pairs of ganglia, corresponding, probably, to the number of primitive segments comijosing the head. The ncavutis cord is thus, in the head, massed together and compacted to form a brain. Fig. 43. Nervous System of Corydohis cormitus. «, "cerebrum ;" b, "cere- brellum;" c, thoracic ganglia, which distribute a nerve to each leg; f Styloids and the sedentary young of Bees, it ends in a blind sac, as they live on liquid food and expel no solid excretions. When well developed, as in the adult insect, it becomes a long convoluted thick muscular tube, subdivided into different parts which perform different functions and have distinct names, taken from analogous organs in the vertebrate animals. This digestive tube is composed of three coats, the outer, or peri- ORGANS OF NUTRITION. 35 toneal; the middle, or muscular; and the inner, or mucous. Tha mucous coat is vai'iously modified, being plaited or folded ; or, c d e h f k b-. Fig. 44. as in the Orthoptera and carnivorous Coleoptera, it is solidified and covered with rows of strong hornj- teeth, forming a sort of gizzard. The alimentary canal is held in place by retractor muscles, but principall}- by exceedingly numerous branches of the main tracheae. This canal (Fig. 45) is subdivided into the mouth and pTict- rynx, the Oisoj^hagus^ supplementary to Avhich is the crop., or " sucking stomach" of Diptera, Lepidoptera, and Hymenoptera ; the proventricnhis, or gizzard ; the ventricuhcs, or true stomach, and the intestine, which consists of the ileum, or short intes- FiG. 44. Anatomy of Sphinx ligustri. m, i, q, the nervous cord resting on the floor of the body; ate, the ganglia form a brain-like organ, much hirgcr than the ganglia of the thorax (/«) and abdomen (7). From the brain is sent off the suboesophageal nerve which surrounds the gullet into whicli the food is conveyed by the maxillae, or spiral tongue («), which, when at rest, is rolled up betweeu the -•abial iialpi (6). From the nei'vous cord is also thrown off a pair of nerves to each pair of legs (as at M, o,p) and a branch, t?, is sent off from above, distributing nerves to the muscles of flight. The heart, or dorsal vessel (e,/), lies just beneath the median line of the body, and is retained in place by muscular bands (as at /) as well as by small tracheal branches. The alimentary canal (,h,j, g), forms a straight tube in the head and thorax; h, the crop, or sucking stomach, which opens into the resophagus; j, the true, chyle- foi'mmg stomach, which contracts posteriorly, and then dilates near its anal outlet into a cloaca (indicated at g, but not distinctly, as it is concealed by the numerous urinary vessels). The urinary vessels also indicated at p, foi-m long tubes (which correspond to the kidneys of Vertebrates), opening into the pyloric end of the stomach. The position of the testes (/;)is the same as that of the ovary, and the dotted line I shows the course of the efferent duct {vas deferens) and also of the oviduct of the female. The figure represents a, longitudinal section of the insect, the legs and ends of the antennje having been removed. — From Newport. 86 THE CLASS OF INSECTS. tine, a,nd the colon and rectum. The latter part, as well as the crop and proveutriculus, are sometimes absent. Of the a2:)]}endages of Hie canal, the first are the salivari/ glands, which are usually long simple tubes, which in the larva, ac- cording to Newport, form the silk vessels. They " empty themselves by a single duct through the spinneret on the floor (labium) of the mouth." In the Ant-lion {Mynneleon) the silk is spun from "a slender telescopic- like spinneret, placed at the extremity of its body," and AVestwood also states that the larva of Chn/sojja spins a cocoon "from the s[)iinieret, at the extremity of the body." These silk glands when taken out of the larva, just as it is about ready to transform, are readily prepared as "gut" for fish-lines, etc., by dr3nng on a board. In the Bees these glands are largely de- veloped to produce a sufficient amount of salivary fluid to moisten the dry pollen of flowers, before it enters the oesophagus. "Bee-bread" consists of pollen thus moistened and kneaded by the insect. The Honey-bee also dissolves, by the aid of the salivary fluid, the wax used in making its cells. Newport believes this fluid is alkaline, and forms a solvent for the other- wise brittle wax, as he has seen this insect "reduce the per- fectly transparent thin white scales of newl}- secreted wax to a pasty or soapy consistence, by kneading it between its man- dibles, and mixing it with a fluid from its mouth, before apply- ing it to assist in the formation of part of a new cell." Insects have no true liver; its functions being performed "by the walls of the stomach, the internal tunic of which is composed of closely-aggregated hepatic cells." (Siebold.) In the Spiders and Scorpions, however, there is a liver distinct from the digestive canal. In the Spiders it is verj- large, enveloping most of the other viscera. Fig. 45. Alimentary tube of Corydahis cornutus. a, oesophagrus; b, proven- triculus; c, ventriciilus; (/, large intestiue; c, urinary tubes; /, ccecum; inal, or great ventral vessel which lies in the abdomen just over the nervous cord, and Avhich is also found in the Scorpion and Centipede. He believes "this vessel to be the chief means of returning the blood from the middle and inferior portion of the body to the posterior extremity of the dorsal Aessel or heart." He strongly suspects that anteriorly this great ventral vessel is connected wdth the aorta. The circulation of Insects, there- fore, is probably as much a closed one as in the Myriapods, for he states that the "blood certainly flows in distinct vessels, at least in some parts of the body in perfect insects, and that vessels exist even in the larva." Observations on the vascula. system are exceedingly difficult from the delicate structure of the vessels, and the subject needs renewed observations to settle these disputed points. The blood is forced through the vessel into the body by regu- lar pulsations. Herold counted thirty to forty in a minute in :i 40 THE CLASS OF INSECTS. full-grown caterpillar ; wc have counted about sixty a minute in the recently hatched larva of Dipic'x- During excitement, the number of pulsations increases in rapidit3\ Newport found the pulsations in a bee, Antho]}1iora^ Avhen quiet, to bo eighty a minute ; but when "the insects were quite lively, and had been exi)0sed to the sun for an hour or two, the number of pulsa- tions amounted to one hundred and forty." He found that the nmnher of pulsations decreased after each moult of the larva of ^SpJ^^vx lirjustri., but increased in force; when it was full grown and had ceased feeding it was thirty. "After it had passed int(j the pupa state the number fell to twenty-two, and afterwards to ten or twelve, and, during the period of hibernation, it almost entirely ceases ; but in the per- fect insect it rose from forty-one to fifty, and when excited by (light around tl:c room it was from one hundred and ten to one iumdrcd and thirty-nine." Orgaxs of EEsriRATiox. All insects breathe air, or, when they live in the water, respire, by means of branchiae, the ah- mixed mechanically with water. Respiration is carried on l)y an intricate system of tubes (pul- monary trachejc) which open by pores (spiracles or stigmata) in the sides of the body ; or, as in aquatic insects, by branchite, or gill-like Hattened expan- sions of the body-wall penetrated by tracheae (branchial trachete). There are normally eleven spiracles, or breathing-holes (Fig. 48), on each side of the body ; each consisting of an oA'al horny ring situated in the peritreme ^'s-48. {1,1(1 closed by a valve, which guards the orifice (Fig. 49). Within this valve is a chamber closed within by another valve which covers the entrance into the tracheae. The air-tube itself (Fig. 50) consists of "an external Fig. 48. Larva of (he Hnmblc-beejupt beginning to change to a pnpa, showing ten pairs of Ktigm.ita In the adult boo, only the third pair is apparent, the remaininc pairs being concealed from view, or in part aborted. In most insects there are usually only nine pairs of stigmata. — Onginal. ORGANS OF RESPIRATION. 41 serous, and an internal mucous membrane, inclosing between them a spirally convoluted fibre, thus giving great strength and flexibility to the tube." Nearly all the air enters through the thoracic and first abdominal spiracles, so that on pinching most insects on the thorax the}' can be U easily deprived of breath and killed. " In some aquatic larvjB such as those of Dyticidm, EristaUs Fig. 49. (Fig. 51^ pupa), and Epliydra, and also in some perfect insects, as in Nepa and Bcmatra, the parts sup- porting the stigmata are prolonged into slen- Fig. 50. der tubes, through which the insect, on rising to the surface, breathes the atmospheric air. Agrion (Fig. 52) affords a good instance of branchiiVi or gill-like expansions of the crust, or skin. It is supposed that these false gills, or branchiae, "aljsorb the air from the water, and convey it by the minute ramifications of the tracheal ves- sels, with Avhich thej^ arc abun- dantly supplied, and which ter- minate in single trunks, into the main tracheae, to be distributed over the whole body, as in insects which live in the open atmosphere." (Newport.) Of branchiiie there are three kinds. The first, as in the larvse and pupae of Gnats, consist of slender fila- ments arranged in tufts arising from a single stem. In the larA'a of Gyrinus and the aquatic caterpillar of a moth, Fig. 40. Cliambev leading into the trachea; a, a, external valve protecting the outer opening of the stigma, or breathing hole; b, c, c, inner and more complicated valve closing the entrance into the trachea (7, Ic); m, conical occlusor muscle closing the inner orifice. — Fmm Strfins Durckhcim. Fig. 50. Portion of a trachea divested of its peritoneal envelope, o, spirally ronvohited fibre, closely wound around the trachea, as at e ; c, origin of a secondary tracheal bran(rh. — From Strniix Durckheim. Fig. 52. One of the three gill-like appendages to the abdomen of the larva and pupa of Agrion enlarged, consisting of a broad leaf-like expansion, i)ernieated by trachea; which take up by endosmosis the air contained in water.— OrUjiiud. A* Fig. 51. Fig. 52. 42 THE CLASS OF INSECTS. Hydrocampa stratiolata, they form short stiff bristles placed along the side of the body. Agrion and Ejihemera, in their larval stages, afford the second kind of branchitie, and Lihellala the third kind, or internal gill, situated in the colon. The Mosquito breathes both by branchia; which form large chib- shaped organs, and by lateral filaments. In those insects that fl^- , most of the tracheoe are often dilated into air-vesicles, so that by filling and emptying them of air the insect can change its specific gravity. That their use is also to lighten the body is shown by their presence in the heavy mandibles and head of the male of Lucanus cervus. In the adult Humble-bee there are two very large vesicles at the base of the abdomen. These vesicles are not found in the larva;, or in the adult forms of creeping insects. The act of resijiration consists in the alternate dilation and contraction of the abdominal segments, the air entering the body chiefly at the thoracic spiracles. As in the Vertebrates the frequency of the acts of breathing increases after exertion. "When an insect is preparing itself for flight, the act of res- piration resembles that of birds under similar circumstances. At the moment of elevating its elytra and expanding its wings, which are, indeed, acts of respiration, the anterior pairs of spiracles are opened, and the air rushing into them is extended over the whole body, which, by the expansion of tlie air-bags, h-, enlarged in bulk, and rendered of less specific gravity ; so that when tlie spiracles are closed at the instant the insect endeavors to make the first stroke with and raise itself upon its wings, it is enabled to rise in the air, and sustain a long and powerful flight with but little muscular exertion. In the pupa and larva state respiration is performed more equally by all the spiracles, and less especially by the thoracic ones." During hibernation the act of breathing, like the circulation of the blood, almost entirely ceases, and the heat of the body is greatly lowered. Indeed Newport has shown that the devel- opment of heat in Insects, just as in Vertebrates, depends on the "quantity and activity of respiration, and the volume and velocity of the circulation." The Humble-bee, according to Newport, possesses the voluntary poioer of generating heat by lireathing faster. He says, confirming Huber's observations. ORGANS OF SECRETION. 43 "the manner in wliich the bee performs her incnb.itor}- office is bj' placing herself upon the cell of :i nymph (pupa) that is soon to be developed, and then beginning to respire at first very gradually. In a short time the respirations become more and more frequent, until at length they are increased to one hundred and twenty, or one hundred and thirty per minute. The body of th-e insect soon becomes of a high temperature, and, on close inspection, is often found to be bathed with per- spiration. When this is the case the temperature of the insect soon becomes reduced, and the insect leaves the cell, and an- other bee almost immediately takes her place. When respha- tion is performed less violently, and consequentl}' less heat is evolved, the same bee will often continue on a cell for many hours in succession. This extreme amount of heat was evolved entirely by an act of the will in accelerating the respiratory ef- forts, a strong indication of the relation which subsists between the function of respiration and the development of animal heat." Organs of Secretion. The urinary vessels, or what is equivalent to the kidneys of the higher animals, consist in In- sects of several long tubes which empty by one or two common secretory ducts into the posterior or "pyloric" extremity of the stomach. There are also odoriferous glands, analogous to the cutaneous glands of vertebrates. The liquid poured out is usually offensive, and it is used as a means of defence. The Bees, Wasps, Gall-flies, etc., and Scorpions, have a poison-sac (Fig. 54: g) developed in the tip of the abdomen. The bite of the Mosquito, the Horse-fl}^, and Bed-bug is thought by New- port to be due to the simple act of thrusting their lancet-like jaws through the skin, and it is not known that these and other insects which bite severely eject any poison into the wound. But in the spiders a minute drop of poison exudes from an orifice at the end of the mandibles, "which spreads over the whole wound at the instant it is inflicted." This poison is secreted by a gland lodged in the cephalo-thorax, and which is thought by Audouin to correspond in position to the salivary apparatus and the silk glands of the AVinged Insects. Organs of Generation. We have already described the external parts. The internal parts of the male insect consist, 44 THE CLASS OF INSECTS. of a duct, tlie ductus ejaculatorius^ which opens into the external inti'omittent organ. This duct extends backwards, connecting with tlie vcsicuke seminales^ wliich lead by tlie vasa deferentia to the testes (Fig. 53). Tlie latter are usually rounded glandular bodies, sometimes, as in Melolontha and Lucanus, numbering six on a side. These organs lie in the abdominal cavity, usually above and on each side of the alimentary canal. The sperm, or fertilizing tluid, contains very active spermatic par- ticles w h i c h are developed in large cells in the testes. Fie:. 53. where they are united into bundles of various forms. In the female, the internal re- productive organs (Fig. 54) are anore simple than those of the other sex. The external open- ing of the female is situated at the end of the oviduct, that leads by two tubes to the ovary, which consists of two or more tul)es (in the Queen Bee one hundred and sixty to one hundred and eighty) in which the ova are developed. On the upper side Fig. 53. Male organs of Athalia centifolire. h, the peni.s, or external portion, in which the ductus ejaculatorius (/) terminates, -which extends backwards, and is connected with the x^esiculm semimtles (e), and rassn deferentia (d) which are con- nected with the epididymis (b), and the testes («). i and I, two pairs of horny plates, surrounded by a horny ring (/.-). i, horny prehensile hooks attached to k. m, two elongated muscular parts inclosing the penis (h).— Frnm Newport. Fig. 54. Female organs of generation of Athalia cent if ol iff,, a, h, c, the eighteen ovarial tubes originating from each of the two oviducts (c), and containing the im- mature eggs ; /, the spcrmatheea ; ff, ]ioison-sac, the poison being secreted ia the secretory vessels h. The poison flows through the oviduct into the sting and thence into the wound made by the sting. 10, the terminal ganglia of the uervous cord. — From Newport. Fig. 54. OKGANS OF GENERATION. 45 of the oviduct are from one to five appendages, the most impor- tant of wliich is the spermutheca (the others being sebaceous ghmds), which receives tlie fertilizing fluid of the male during sexual union, and in which, according to Darwin, the male ele- ment "is enabled to keep alive four or five years." Insects bisexual. With the exception of the Tardigrades, which are doubtfully referred to the Mites (Acarina), there are no hermaphrodites among Insects, that is, there are no individ- uals having both male and female organs, and capable of self- impregnation. On the contrary, the sexes are distinct ; Insects ai'e bisexual. Hermcqjhi'odites, so-called. Cases not unfrequently occur in which from arrest of development of the embryo, the sexual organs are imperfectly developed, so as to present the appear- ance of being both male and female. "Siebold has investigated some hermaphrodite Honey-bees belonging to the Italian race, obtained from a Dzierzon hive at Constance. He found in many of them a combination of sexual characters, not onl}' in the external parts, but also in the generative organs. The mixture of the external characters is manifested sometimes only in the anterior or posterior part of the body, sometimes in all parts of the body, or only in a few organs. Some specimens pre- sent male and worker characters on the two sides of the body. The development of the internal organs is singularly correla- ted with these peculiarities of external organization. The sting, with its vesicle and gland, is well developed in hermaphrodites with the abdomen of the worker ; soft in those with the drone- abdomen. The seminal receptacle, when present, is empty. The ovaries contain no ova. In the hermaphrodites with the drone-abdomen, the male sexual organs are well developed, and the testes contain spermatozoids. Frequently with testicular and ovarian organs present on each side, the epididymis and copulatory apparatus are well developed, and an imperfect poison-apparatus exists. In these cases the tube contains spermatozoids, but there are no ova in the ovaries. The her- maphrodites are thrown out of the cell by the workers as soon as they emerge, and speedily perish. Siebold ascribes the pro- duction of these hermaphrodites to an imperfect fecundation of the ovum." (Zeitschrift fiir Wissensehaftliche Zoologie, 18G4, p. 73. See Giinther's Zoological lieview for 18G-I.) 46 THE CLASS OF INSECTS. Mr. Dunning describes a specimen of Fidonia piniaria^ "which was sexually a female, and the abdomen was appar- ently distended with eggs ; the general color was midway be- tween the colors of the ordinary male and female, but the size and markings were those of the male. (Transactions J^nto- mological Society, London, Aug. 7, I860.) Professor West- wood states that "he had an Orange-tip Butterfly {Anthocharis cardamines) , which was female in every respect, except that on the tip of one fore- wing were about a dozen of the bright orange scales which characterize the male." The P2gg. Professor H. J. Clark (Mind in Nature) defines an egg to be a globule surrounded by the vitelline membrane, or yelk-envelope, which is protected by the chorion, or egg- shell, consisting of "two kinds of fluid, albumen and 0/?, which are always situated at opposite sides or poles." "In the earli- est stages of all eggs, these two poles shade oflT into each other," but in the perfectly developed egg the small, or albu- iuinous pole, is surrounded by a membrane, and forms the Purkinjean (germinal) vesicle ; and thirdly and last, the inner- most of the three globules is developed. This last is the Wa,gnerian vesicle, or germinal dot. The oily matter forms the yolk. Thus formed, the egg is the initial animal. It becomes an animal after contact wdth the male germs (unless the product of organic reproduction), and the egg-shell or chorion is to be considered as a protection to the animal, and is thrown ofl" when the embryo is hatched, just as the larva throws off its skin to transform into the pupa. So that the egr/state is equivalent to the larva state, and hence there are four stages in the life of an insect, i. e. the egg, the larva, the pupa, and the imago, or adult state. The egg is not always laid as a perfect egg (Clark). It sometimes, as in the Ants, continues to grow after it is laid by the parent, like those of frogs, which, according to Clark, "Are laid before they can hardly be said to have become fully formed as eggs." Again, others are laid some time after the embryo has begun to form ; and in some, such as 3felopJiagns and Branla, the larva is fully formed before it is expelled from the oviduct. THE EGG. 47 Eggs are usually small in proportion to the size of the parent; but in many minute forms {i.e. Pulex, Pcdiculas, etc.) they are proportionately mucli larger. In shape eggs are either splierical or oblong. In some there are radiating append- ages at one end, as in those of NejKi and Ranatra ; or they are provided with a single stalk, as in ChrysojM, Cynqys, and Ojihion. The eggs of most Hymeuoptera, Diptera, and many Coleop- tera are usually cylindrical ; those of Lepidoptera are more generally spherical. The eggs of the Mosquito are laid in a boat-shaped mass, which floats on the surface of quiet pools, while those of the Chrysopa^ or Lace-winged Fly (Fig. 55), are supported on long pedicels. They are almost invariably laid near or upon objects des- tined to be the food of the Fig. 55. future larva. Thus the Copris, or "Tumble-bug," places its egg in a ball of dung which it rolls away to a secure place ; the Flesh-fly oviposits on meat ; and all vegetable-feeders lay their eggs on the food-plant where the larva, upon its exit from tlie egg, shall readily find an ample supply of food. The posterior end of the egg is more often the fixed one, and it may thus be distinguished from the anterior pole. In the eggs of some Diptera and Orthoptera, the ventral side of the. embryo, according to Gerstaecker, corresponds to the convex side of the egg, and the concave side of the latter corresponds to the dorsal region of the embryo. The surface of the chorion, or egg-shell, which is dense and brittle, is often covered by a mosaic- work of more or less regu- lar facets. In many small eggs the surface is onl}^ minutely granulated, or ornamented with ribs and furrows, as in those of many Butterflies. The Micropyle. On the anterior end (though sometimes at both ends) of the egg is one or more pores of exceeding minuteness, through which the spermatozoa (more than one of which, according to Darwin, is requisite to fertilize an ovule) enter to fertilize the egg-contents. In some cases these micropyles are scattered over the whole surface of the egg. Fig. 56 a represents the micropyles of Nepa cinerea, consisting 48 THE CLASS OF INSECTS. of a whorl of long bristles. Those of Locusta viridissima (Fig. bC)b) slisihtly resemhle toadstools. Fig. oGc represents the an- terior pole of the egg with the micropyles of Pyrrliocoris (ipterus. — {From Gerstaecker.) This contact of a male sperm-cell with the yolk is tlic fertilization of the egg. From this moment begins the life of the embryo. Fertiliza- tion of the female germ by * IS- 5U. means of the male sperm, through the congress of the sexes, is the rule with bisexual animals, but there are exceptions among insects. An embryo ma}^ start into being without the interposition of the male ; to this mode of generation has been applied by Leuclvart the term Parthenogenesis. Among certain species of insects there are some individuals which, liy a sort of budding process, and with- out the aid of the male element, throw oif summer broods, con- sisting of '^' asexual" individuals, which, as winter approaches, are succeeded by a brood of true males and females, the latter of which lay eggs. This phenomenon, called by Steenstrup "alternation of generations," has been observed among a com- paratively few species, and the apparent design of such an anomalous mode of reproduction is to afford an immense num- ber of individuals, thus providing for the continuance of the species. The individuals in wliom this budding process takes place are called "asexual" because, though they may resemble the female sex outwardly, their sexual organs are only partially developed. This Inidding process is the same in kind with that observable in the Jell3-tish, which throw off by parthenogen- esis, or alternations of generations, summer broods of immense extent, but in winter propagate by true eggs. Huxley has studied the development of Aphis by parthenogenesis, the anomalous nature of which had previously been discovered by Bonnet, Trembly, Lyonet, Degeer, Kyber, and others, and arrives at the following conclusions : "1. Ova deposited by impregnated female Aphides in autumn are hatched in the spring. ALTERNATION OF GENERATIONS. 49 2. From these ova viviparous, and, in the great majority of cases, apterous forms proceed. o. Tlie broods to wliich these give rise are either winged or ppterous, or both. 4. The number of successive broods lias no certain limit, but is, so far as we know at present, controlled only by tempera- ture and the supply of food. 5. On the setting in of cold weather, or in some cases on the failure of nourishment, the weather being still warm, males and oviparous females are produced. 6. The males may be either winged or apterous. 7. So far as I am aware, there is no proof of the existence of any exception to the law that the oviparous female is apte- rous. 8. Viviparous Aphides may hybernate, and ma}' co-exist with oviparous females of the same species." (Linnseau Transac- tions, xxii, p. 198.) The origin of the viviparous, asexual, or agamic (from the Greek o, without ; game^ marriage) individual, as it may be more properly called, is, up to a certain stage, the same as that of the true egg, i.e. luitil the germ {psendovum) of the former is detached from the false ovary (pseudovarium). "From this point omvards, however, the fate of the pseudovum is different from that of the ovum. The former begins at once to be converted into the germ ; the latter accumulates yelk-sub- stance, and changes but little. Both bodies acquire their mem- branous investment rather late ; within it the pseudovum becomes a living larva, while the ovum is impregnated, laid, and remains in a state of rest for a longer or shorter period. "Although, then, the pseudovum and the ovum of Aphis are exceedingly similar in structure for some time after they have passed out of the condition of indifferent tissue, it cannot bo said that the sole difference between them is, that the one re'>'*^oral region, including the antennary ^ or first segment of the head, canying the organs of vision ; namel}', the ocelli and com- pound eyes, and the organs of sense, or an- tenna?) ; and the other behind the mouth (pastoral) consisting of the mandibular, or second segment, tho first maxillary, or third segment, and the second maxillary, or labial, beiiig the fourth and last segment. At a later period the embryo is quite full}'- formed, and is about read}^ to leave the egg. The three regions of the body are now distinct. The articulations of the tergum are present, the 3'olk-mass being completel}' inclosed by the tergal walls. Fig. 61. The embryo taken from the egg, but nearly ready to hatch, t, the dotted line crosses the main trachea, going throngh the yolk-mass, now restricted to the thoracic region. At x, the trachea; send oflf numerous branches around an enlargement of the intestine (colon), where the blood is aerated; better seen in fig. fi2. The abdomen consists of eleven segments, the last being a minute triangular piece. THE DEVELOPMENT OF INSECTS. 59 The bod}' is so bent upon itself that the extremities of the second maxilhie just overlap the tip of the abdomen. The two limbs of the labium are now placed side by side, with the prominent spinous appendage on the outer edges of the tip. These spines are the rudiments of the labial palpi. The general form of the embryo at a still later period (Fig. 61), on being taken from the egg and straightened out, re- minds us strikingly of the Thj-sanura, and, in these and other re- spects, tend to prove that the Poduroe and LepismjB, and allied genera, are embryonic, degraded forms of Neu- roptera, and should therefore be considered as a family of that sub- order. Seen laterally, the body gradually ta- pers from the large head to the pointed ex- tremity. The body is flattened from above downwards. At this stage the appendages are still closely ap- pressed to the body. Just before the ex- clusion of the embryo, the legs and mouth- parts stand out freer from the bod}^ The labium, especially, assumes a position at nearly right angles to the body. The antenna?, mandibles, and maxilhie have taken on a more definite form, being like Fig. G2. The larva just hatched and swimming in the water. N, ventral cord or nervous ganglia; d, ilorsal vessel, or "heart," divided into its chambers. The anal valves at the end of the abdomen, which open and shut during respiration, are represented as being open. Both of the dotted lines cross the tracheae. X, net- work of the tracheae, surrounding the cloaca. Fig. 62. 60 THE CLASS OF INSECTS. that of the young larva, and stand out fi-ec from the body. The head is much smaller in proportion to the rest of tlie body, and bent more upon the breast. The Larva (Fig. 62) when hatched is about five hundredths of an inch in length. The head is now free and the antenniB stand out free from tlie front. Tlie thorax has greatly diminished in size, while the abdomen has become wider, and the limbs very long; and the numerous minute tubercles, seen in the preceding stage, have given origin to hairs. The dorsal vessel can now, for the first time, be seen. AVlien in motion, the resemblance to a spider is most striking. The flow of blood to the head, and the return currents through the lacunar or venous circulation along the side of the body were easily observed. The vessels were not crowded with blood disks, the latter being few in number, only one Fig. 64. or two passing along at a time. Two currents, pass- ing in opposite directions, were observed in the legs. Fig. G3. Side view of the head of the larva of Diplax Ijefoi'e the first moult, c, deciduous tubercles terminating in a slender style; their use is unknown; they have not been observed in the fall-grown larva, r, the compound eyes. 1, the three jointed antenna;, the terminal joint nearly three times as long as the two basal ones. 2, the mandibles, and also enlarged, sliowing the cutting edge divided into four teeth. 3, maxilhe divided into two lobes : (/, the outer and anterior lobe, 2-jointed, the basal joint terminating in two sctre; and a, the inner lobe concealed from view, in its natural po.'^ilion, by the outer lobe, <^ 4, the base or peiliccl of the second maxilL-ie, or labium, the expanded terminal i>ortion being drawn sep.a- rately; rf and «, two movable stout styles representing, jjerhajis, the labial palpi; the lobe to which they are attached is multidentate, and adapted for seizing pre}'; on the right side the two styles are appressed to the lobe, .r represents, perhaps, the ligula; but we have not yet studied its homologies carefully: this part is attached to a transversely linear piece soldered to the main part of the labium, y, the Hth abdominal ring, with its pair of conical anal styles, z, the last tarsal joint and iiair of long slender claws. Fig. ()4. The i)upa of Diplax, having rudimentary wings, in which the eyes are much larger, and the legs much sliorter than in the I'ecently h."itched larva; in- troduced to be compared with the young larva. Figs. 57-64, original. I TRANSFORMATIONS OF THE INSECT. 61 On review it will be seen how remarkable are the changes in form of the insect before it is hatched, and that all are the result of simple growth. We have seen that the two ends of the bod}' are first formed, and that the under side of the bod>' is formed before the back ; that the belly is at first turned out- wards, and afterwards the embryo reverses its position, the back presenting outwards. All the appendages are at first simple protrusions from the body-walls, and new segments are interpolated near the tip of the abdomen. These changes take place very rapidly, within a very few days, and some of the most important and earlier ones in a few hours. We can now better understand that the larva and pupa stages are the result of a similar mode of growth, though very marked from being in a ditferent medium, the insect having to seek food and act as an independent being. Transformations of the Insect. We have seen that during the growth of the embryo, the insect undergoes remark- able changes of form, the result of simple growth. The meta- morphoses of the animal within the egg are no less marked than those which occur after it has hatched. It will also be seen that the larva and pupa stages are not always fixed^ defi- nite states, but only pauses in the development of the insect, concealing beneath the larva and pupa skins the most impor- tant changes of form. The process of hatching. No other author has so carefully described the process of hatching as Newport, who observed it in the larva of Meloe. "When the embryo larva is ready for its change, the egg-shell becomes thinned and concave on that side which covers the ventral surface of the body, but is nuich enlarged, and is more convex on the dorsal, especially towards the head. The shell is then burst longitudinally along the middle of the thoracic segments, and the fissure is ex- tended forwards to the head, which then, together with the thoracic segments, is partially forced through the opening, but is not at once entirely withdrawn. The antennae, parts of the mouth, and legs are still inclosed within separate envelopes, and retain the larva in this covering in the shell. Efforts are then made to detach the posterior segments of the body, which 62 THE CLASS OF INSECTS. are graduall}' released, and with them the antennae, paliji, and legs, and the larva removes itself entirely from the shell and membranes. In this process of evolntion the yonng Meloe throws otl" two distinct coverings : first, the shell with its lining membrane, the analogue of the membrane in which, as I have elsewhere shown,* the 3omig Mjriopod is inclosed, and re- tained several days after the bursting of the ovum, and which represents in the Articulata, not the allantois, but apparently the amnion, of Verteln-ata ; next, the first, or fVetal decid nation of the tegument, analogous probably to the first change of skin in the Myriopod, after it has escaped from the amnion, and also to the first change which the 3'oung Arachnidan invariably undergoes a few days after it has left the egg, and before it can take food. This tegument, which, i)erha])s, may be analo- gous to the remix caseosa of Vertebrata, tin-own off at the instant of birth, is left by the young INIeloe with the amnion in the shell ; and its separation from the body, at this early period, seems necessar}- to fit the insect for the active life it has commenced." (Linn. Trans, xx. p. 30G, etc.) The larva state. The larva (Latin larva, a mask) was so called because it was thought to mask the form of the perfect insect. The larvae of Butterflies and Moths are called cater- pillars; those of Beetles, ^r?<6s; and those of the two-winged Flies (Diptera) maggots; the larvae of other groups have no distinctive common names. As soon as it is hatched the larva feeds voraciously, as if in anticipation of the coming period of rest, the pupa state, for which stores of fat (the fatty bodies) are developed for the suppl}" of fat globules out of which the tissues of the new body of the pupa and imago are to be formed. Most larvae moult, or change their skin, four or five times. In the inactive thin-skinned larvte, such as those of Bees, A¥asps, and Gall-flies, the moults arc not ai)parcnt ; as the larva increases in size it out-grows the old skin, which comes off in thin shreds. But in the active larvif, such as cater- pillars, grasshoppers, and grubs', from the rapid absorption of vessels in the outer layer of the skin, just before the change, * Philosophical Transactions, Pt. 2, lS41,p. 111. TRANSFORMATIONS OF THE INSECT. 03 't becomes hard and dry, and too small for the growing in- sect, and is then cast ort' entire. A series of bee-larvtii can be selected showing a graduation in size and form from the egg and recently hatched larva np to the full-grown larva. In the caterpillar and other active larvte, there are usually four or live stages, each showing a sudden and marked increase in size. Newport states that the caterpillar of ASj)hinx ligustri moults six times, and at the last moult be- comes a third larger than at any earlier period ; the larva of Arctia caja moults from five to ten times. A few days before the assumption of the pupa state, the larva becomes restless, stops eating, and deserts its food, and usuall}- spins a silken cocoon, or makes one of earth, or chips, if a borer, and there prepares for the change to the pupa state. During this semipupa period (lasting, in many insects, only for a day or several days, but in some Saw-flies through the winter) the skin of the pupa grows beneath that of the quies- cent larva. While the worm-like larva exhibits no trire- gional distinctions, the muscles of the growing pupa contract and enlarge in certain parts so as to modify the larva form, until it gradually assumes the triregional form of the adult insect, with the differentiation of the bod}?^ into a head, thorax, and abdomen. In a series of careful studies, abundantly illustrated with excellent plates, Weismann has recently shown that Swammer- dam's idea that the pupa and imago skins were in reality already concealed under that of the larva is partiallj'^ founded in truth. Swammerdam states, " I can point out in the larva •all the limbs of the future nymph, or Culex, concealed beneath the skin," and he also observed beneath the skin of the larvae of bees just before pupating, the antenna?, mouth-parts, wings, and limbs of the adult. (Weismann.) During its transformations the pupa skin is developed from the hypodermis, or inner layer of skin. This peals off, as it were, from the inner layer of the old larva skin, which soon dries and hardens, and is throAvn off. Meanwhile the muscles of the body contract and change in form, thus causing the origi- nal segments of the lai'va to infold and contract at certain parts, gradual!}- producing the pupa form. If, during this period, the 64 THE CLASS OF INSECTS. insect be examined at intervals, a series of slight changes of form may be seen, from the larva to the imago state. In some cases each change is accompanied by a moult, as in the "ac- tive" Ephemera, Avhere Lubbock counted twenty one moults. As a general rule, then, it may be stated that the body of the larva is transformed into that of the imago ; ring answer- ing to ring, and limb to limb in both, the head of the one is homologous with that of the other, and the appendages of the larva are homologous with the appendages of the imago. Weismann has shown that in the larva of the Meat-fly, Mxisca vomitoria, the thorax and head of the imago are developed from what he calls "imaginal disks." These disks are minute isolated portions of the hypodermis, which are formed in the embryo, before it leaves the egg, and arc held in place within the body-cavity of the larva l\v being attached either to nervet, or trachea^, or lioth. After the outer layer of the larva skin dries and hardens, and forms the cask-shaped j^^^r^jar/????;, tliL- use of which corresponds to the cocoon of moths, etc., thesf imaginal disks increase in size so as to form the tegument ol' the thorax and head. The abdomen of the Meat-fly, however, is formed by the direct conversion of the eight hinder segment:* of the body of the larva, into the corresponding ^;egments of the imago. Accompanying this change in the integurrient ther'.» is u destruction of all the larval system of orgcms ; this is either total or effected by the gradual destnic<^Jon of tissues. Now we see the use of the "fatty body;" this breaks up, setting- free granular globules of fat, which, fis we have seen in the embryo, produces by the multiplication of cells the new tissues of the pupa. Thus the larva-skin is cast aside, and also the softer organs within, but the formation of new tissues keeps even pace with the destruction of the old, and the insect pr^ serves its identity throughout. The genital glands, however are indicated csen in the embryo, and are gradually develope>( throughout the growth of the insect, so that this histolysis, or destruction of tissues, is not Avholly complete. The quiescent pupa-state of Musca is long-continued, and its vitality is latent, the acts of respiration and circulation being almost suspended. (Weismann.) TKANSFOllMATIONS OF THE INSECT. T.') In the metamorphosis of Corethra, a Mosquito-hke Fly, which is active both in the larva and pnpa states, '"the segments of the larva are converted directly into the corresponding seg- ments of the body of the imago, the appendages of the head into the corresponding ones of the head of the imago ; those of the thorax are produced after the last moult of the larva as diverticula of the hypodermis round a nerve or trachea, from the cellular envelope of which the formation of tissue in the interior of the appendages issues. The larval muscles of the abdominal segments are transferred michanged into the imago ; the thoracic muscles peculiar to the imago, as also some additional abdominal muscles, are developed in the last larval periods from indifferent cellular cords which are indi- cated even in the egg. The genital glands date back to the embryo, and are gTadually developed ; all tlie other systems of organs pass with little or no alteration into the imago. P^atty body aione or inconsiderable. Pupa-state short and active." (Weismann.) As the two tj'pes are most clearly discriminated by the l)resence or absence of true imaginal disks, AYeismann suggests that those insects which undergo a marked metamorphosis might be divided into Insecta discota (or Insects with imaginal disks), and those without, into Insecta adiscota. The metamorphosis of Corethra may prove to be a type of that of all insects which are active in their preparatory stages ; and that of Mitsca typical of all those that are quiescent in the pupa-state, at least the Lepidoptera and those Dipteia which have a coarctate * pupa, together with the Coleoptera and those Neuroptera in which the metamorphosis is complete, as Phrij- ifa)iea, Ilemerohius^ etc. The transformations of the Ilumble-bee are easilj' observed by taking a nest after the first brood have matured, when we shall find individuals in all stages of development from the larva to the imago state. The figures below show four stages, but in reality there is every gradation between these stages. 'The larva? of somo of the higher Diptcra spin .1 slight cocoon, while the tnio flics, such as the Muscida,' and Syrphida;, etc., change to pupa' within the larva skin which contracts into a cylindrical "pnparium" coiTcsponding in use to the i'ocoon; such pujia? arc called "coariitatc."' 5 66 THE CLASS OF INSECTS. Fig. 64 shows what we may call the semipupa, concealed by the old larval skin. There are ten pairs of stigmata, two thoracic and eight abdominal. The head of the semi-pnpa lies nnder the head (a) and prothoracic ring (b). The basal ring of the abdomen (c), or fourth ring from the head, is un- changed in form. This figure also will suffice to represent Fis. 64. Fig. 65. Fi?. m. Fig. G7. the larva, though a little more produced anteriorly than in its natural form. In another stage (Fig. 65) of the semi-pupa, the larval skin is entirely sloughed off, the two pairs of wing-pads lying paral- lel, and very equal in size, like the wings of Neuroptera. The thoraco- abdominal ring, or 2'>ropodeum (c), is distinguished by its oblong spiracle («), essentially differing from those on the abdomen. At this point the body contracts, but the head TRANSFORMATIONS OF THE INSECT. 67 and thorax together are yet, as still more in the previous stage, much smaller than in the pupa, and there is still a con- tinuous curve from the tip of the abdomen to the head, (y, antenna ; /t, lingua, maxillffi, and palpi ; i, fore-legs ; j, mid- dle legs ; A', meso-scutum ; Z, meso-scutellum ; w, spiracle of the propodeum.) In a succeeding stage (Fig. 66) of the semi-pupa, the head and thorax together nearly equal in size the abdomen, and the propodeimi (c) has become entirely transferred to the thorax. The head has become greatly enlarged ; the rings are very un- equal, the hinder pair are much smaller, and overlaid by the anterior pair ; the three terminal pair of abdominal rings, so large in Fig. (Jb, have been absorbed, and partially inclosed in the cavity of the abdomen ; and there has been a farther dif- ferentiation of the ring into the sternite (rf), pleurite (e), and tergite (/). (a, eye; /i, lingua; o, ovipositor, two outer rhabdites exposed to view.) The abdominal spiracles in Figs. 65 and 66, are represented by a row of dots. In the pupa they are concealed by the tergites, which overlap the sternites. Fig. 67 represents the pupa state, where the body has become much shorter, and the appendages of the head and thorax greatly ditferentiated ; the external genital organs are wholly retracted within the cavity of the abdomen ; the head is freer from the body, and the whole bulk of the head and thorax together, in- cluding the appendages, greater than that of the abdomen. These changes of form, assumed by the insect in its passage from the larva to the pupa state, are nearly as striking as the so-called "hypermetamorphosis" of Meloe and Sitaris described by Newport and Fabre. (/, mesoscutellum ; p, cly- peus ; g, maxillse with the palpi ; r, lingua.) We have also observed similar changes in the semi-pupa of a Tineid larva, which we found in the mud-cells of Och/nenis alhoplialeratus. There were over a dozen specimens in different stages of growth from the larva to the pupa, which were but partially paralyzed by the well-directed sting of the intelligent wasp, so that some continued to transform into perfect pupsv. The following changes were noticed : the larva straightened out, and became a little shorter, the prothoracic ring remaining the same ; the head of the pupa being beneath it ; the meso- 68 THE CLASS OF INSECTS. tiioracic ring enlarged, swelling and ronnding above and on the .sides, and with this increase in size drawing the nieta-thorax forwards. The first visible portion of the pupa beneath is the inesothorax. The tlioracie legs of the larva are now con- stricted at their base, and have become useless. In the next stage, the most important change noticed is in the metatliornx, which now becomes broadly heart-shaped. In a succeeding stage, the whole thorax bulges out, and is much larger and clearl}- distinguished from the head and abdomen. Tlie prothorax of the larva disappears, and that of the jjupa takes its place. The occiput of the pupa, just before the larva- skin is thrown off, can be distinctly seen under the larval occi- put, pushing aside each half of the latter. In the last stage of Bombus just before the imago leaves its cell, the body and limbs are surrounded b}^ a thin pellicle. This pellicle also envelops the moth, just before it leaves the pupal state, and is cast off when it moults the pupa-skin. This is probably identical with the skin cast by the active subimago of E'phemera^ soon after it has taken its flight. Westwood also considers this subimago skin identical with iliat covering the bodies of coarctate Diptera, as in Eristalis. Newport states, that when the imago of Sj^Mnx is about to east off the pupa-skin the abdominal segments are elongated beyond their original extent, this being the first part of the insect that is entirely freed from its attachment witliin the pupa-case. After this the thorax slits down, and the body is drawn out of the rent. In the Butterfl}" the Avings mature in a few moments, but those of S/)hinx being tliicker, require two or three hours. Newport (Philosophical Transactions, London, 1832 and 1834) has detailed with great minuteness the internal changes of Sjyhinx llgvstri while transforming. The most nua-ked changes are in the nervous and digestive systems. Several anomalous modes of metamorphosis have been ob- served, one in Diptera and the other in Sitaris and JMoe. The development of the latter insect will be noticed beyond. Sir John Lubbock has described the singular metamorphosis of Lonchojotera, which he considers to be allied to /Sargus, though tlie adult stages differ greatly. The larva; are oblong TRANSFORMATIONS OF THE INSECT. 69 ovate, flattened, with four long setre in front and two behind, witli the sides of the body eniarginate and spinukited. They were found under logs. "When the larAa is full grown, it de- taches itself from the skin, which retains its form, and within which the insect changes into a white opaque fleshy grub con- sisting apparently of thirteen segments which graduall}- dimin- ish in size from one end to the other. There are no limb-cases. According to analogy the pupa should be ' incomplete ; ' it is probable, therefore, that the legs and wings make their appear- ance at a later stage. If this be so the perfect form is only attained after passing tlu'ough three well-marked stages. I re- gi"et, however, that the specimens at my disposal did not enable me to decide this point." (Trans. Ent. Soc. London, Third Ser. i, 1862.) Ilalida}' states that Tlirips goes through a propxqja and pupa stage. There are five well-defined stages in the Homopterous Typhlocyha, and more than three in Apliis. Yersin has noticed several stages in the development of Gryllus camjjestris, and the genus Fsocus has four such stages. The duration of the different stages varies with the changes of the seasons. Cold and damp weather retards the process of transformation. Re'aumnr kept the pupa of a Butterfl}' two years in an ice-house before, on being removed to a warm place, it changed to a butterfl}'. Chrysalids survive great alter- nations of heat and cold ; they may be frozen stiff on ice, and then, on being graduallj' exposed to the heat, thaw out and finish their transformations. Retrograde Development. There are certain degradational forms among the lowest members of each group of Insects which imitate the group beneath them. The Tardigrades (which are considered by some authors to be allied to the Mites) are mimicked by the low parasitic worm-like Demodex follicnlorum ; the low Neuroptera, such as Lcpisma. imitate the Myriopoda ; and the wingless Lice remind us of the larva? of the Neuropter- ous Hemerobms. Among the Coleoptera, the history of Stylop>s affords a strik- ing example. The active six-footed larva is transformed into the strange bag-like female which takes on the form of a cylin- drical sac, the head and thorax being consolidated into a 70 THE CLASS OF INSECTS. minute flattened portion. The process of degradation here seems carried out to its farthest limit. Thus the degraded forms of the lower series of Hexapods take on a Myriopod aspect. In the more higl% cei)hulized Diptera, Lepidoptera, and Hymenoptera the degraded forms are modelled on a higher articulate type. The idea of a divis- ion into three regions is involved. Thus the wingless forms of Flies, such as the Bird-louse, Nirmus; the Bat-tick, Nycte- ribia ; the Bee-louse, iJraM/a; and C7iio?iea resemble strikingly the biregional Arachnids. In the wingless female of Orgyia and the Canker-worm moth, the head is free, but the thorax is merged into the abdomen. The resemblance to the lower insects is less striking. The worker ants and wingless Ichneumons, Pezoinochns, still more strictly adhere to the type of their suborder, and in them the triregional form of the bod}- persists. Among the first of the examples here cited we liaAC seen the workings of a law, by which mcjst degraded forms of insects (and this law is exerted with greater force in Crustacea) tend to revert to the worm-like, or, as we may call it, the archetyjyal, form of all Articulata. We have seen that many winged forms mimic the groups above them, whereas the wingless degraded species revert to a worm-like form. In either case, the progress is towards a higher or a lower form. The latter is the more exceptional, as the evolution and growth of all animals is upwards towards a moi'e specialized, differentiated form. The Imago. After completing its transformations the adult insect immediately seeks to provide for the propagation and continuance of the species. The sexes meet, and, soon after, the male, now no longer of use in the ins(>ct economy, perishes. The female hastens to lay her eggs either in, upon, or near what is to be the food of the young, and then dies. This period generally occurs in the summer and autumn, and during the winter the species is mostly represented bj^ the egg alone. Rarely does the adult insect hibernate, but in man}' species the pupa hibernates to disclose the adult in early summer. The larva seldom, as such, lives through the winter. Re'aumur kept a virgin butterfly for two years in his hot- house. From this it would seem that the duration of the life GEOGRAPHICAL DISTRIBUTION. 71 of an insect may be in this way greatlj- prolonged. Most in- sects live one year. Hatcliing from tlie egg in early summer, tlie^^ pass through the larva state, and in the autumn become pupae, to appear as imagos for a few days or Aveeks in the succeeding summer. Man}' Lepidoptera are double-brooded, and some have even three broods, while the parasitic insects such as Lice and Fleas, and many Flies, keep up a constant succession of broods. Warmth, Mr. E. C. R. Jordan remarks in the Ento- mologists' Monthly Magazine, has much to do with rapidity of development, as insects may be forced artificially into hav- ing a second brood during the same season. Some Coleoptera, such as the Lamellicorns, are supposed to live three years in the larva state, the whole time of life being four j-ears. The Cockchafer (Melolontha) of Europe is three years in an-iving at the perfect state, and the habits of the Goldsmith Beetle {Cotaljoa lanigei-a), according to Rev. Samuel Lockwood (American Naturalist, vol. 2, p. 186), and of the June Beetle, and allied genera, are probably the same. Geographical Distribution. The insect-fauna of a coun- try comprises all the insects found within its limits. The F(^lar, Temperate, and Tropical zones each have their distinct insect-fauna, and each continent is inhabited by a distinct assemblage of insects. It is also a curious fact that the insect- fauna of the east coast of America resembles, or has many an- alogues in, that of the Eastern hemisphere, and the west coast of one repeats the characteristics of the west coast of the other. Thus some California insects are either the same spe- cies or analogues {i.e. representative species) of European ones, and the Atlantic coast affords forms of which the ana- logues are found in Eastern Asia and in India. This is corre- lated with the climatic features which are repeated on alternate sides of the two hemispheres. The limits of these faunae are determined by temperature and natural boundaries, i. e. the ocean and mountain ranges. Thus tlie insect-fauna of the polar regions is much the same in Europe, Asia, and North America ; certain widely spread polar species being common to all three of these continents. When we ascend high mountains situated in the temperate 72 THE CLASS OF INSECTS. zone, wliotc sumiuits nearly reach the snow-line, we find a few insects which are the same or very simikir to those of the poUir regions ; such an assembhige is called an Alpine fauna. The insect-fauna of each great continent may be divided into an Arctic, or polar, a Temperate, and a Tropical fauna, and an Alpine fauna if there are mountains in the warm latitudes whicli reach near the snow-line. Mountain barriers, inland seas, des- erts, and peculiarities in the flora (or collection of plants peculiar to a certain district), are boundaries of secondary importance in limiting the distribution of species. On the other hand insects are ditfused by winds, rivers, oceanic currents, and the agency of man. By the latter im- portant means certain insects become cosmopolitan. Certain injurious insects become suddenly abundant in newl}' cultivated tracts. The balance of nature seems to be disturbed, and insects multiplying rapidly in newly settled portions of the country, become terrible pests. In the course of time, how- ever, the}^ seem to decrease in numbers and moderate their attacks. Insect-faunae are not limited by arbitrar}^ boundaries, but fade into each other by insensible gradations corresponding in a general way to the changes of the temperature of diflerent portions of the district they inhabit. The subject of the geographical distribution of insects, of which we have as yet but given the rudiments, may be studied to great advantage in North America. The Arctic insect-fauna comprises Greenland, the arctic American Archipelago, and the northern shores of the continent beyond the limit of trees. A large proportion of the insects found in this region occur in arctic Europe and arctic Asia, and are hence called circum- polar, while other species are indigenous to each country. Again, the arctic fauna of Labrador and Hudson's Bay ditfers from that of the arctic portions of the region about Behring's Straits, certain species characterizing one side of the continent being replaced by representative species which inhabit the opposite side. The Alpine fauna of the White Mountains consists, besides a very few peculiar to them, of circumpolar species, which ai-e now onl}" found in Labrador and Greenland, and which are GEOGRAPHICAL DISTKIBUTION. 73 supposed to be relics of a glacial fauna which formerly inha]> itecl the northern part of the temperate zone, and in former times followed the retreat of a glacial, or arctic climate from the low-lands to the Alpine summits. These patches, or out- liers, of an Arctic fauna, containing however a preponderance of subarctic forms, also occur in the colder parts of New England. The subarctic fauna is spread over British North America, stretching north-westerly from the interior of Labrador and the northern shores of the St. Lawrence, following the course of the isothermal lines which run in that direction, and north of Avhich no cereals grow. There are subarctic forms which inhabit the shores of the Bi\\ of Fundy, especially about Eastpoit, Maine, where the fogs and cold arctic marine cmrents lower the climate. Dr. J. L. Leconte, in a paper on the Coleoptera of Kansas and Eastern New INIexico (Smithsonian Contributions to Knowl- edge), thus subdivides the Coleopterous fauna of the United States, and gives a useful map to which the reader is referred. "The whole region of the United States is divided by merid- ional, or nearly meridional lines into three, or perhaps four, great zoological districts, distinguished each by numerous peculiar genera and species, which, with but few exceptions, des a gigantic May-fly, Platephemera antiqua (PI. 1, fig. 3) ; Lithentomum Harttii (PI. 1, fig. 5) ; Homothetus fossi- Us (PI. l,fig. 7) ; and Xenonevra avtiqnoriim which is supposed to bear a stridulating organ like that of the Grasshoppers, so that he "is inclined to believe there were chirping Neu- roptera in those days." Ascending to the Carboniferous rocks, insect-remains appear more abundant. At Morris, Illinois, have been collected some remarkable forms. Among them are Miamia Bronsonii Dana (PI. 1, fig. 1), allied to the White Ants and Hemeristia occi- dentalis Dana, allied to Hemerohms and ChrysojM. From the same locality Mr. IIar';,er has described Arthrobjcosa antiqua (Fig. 68), a singular form with a jointed abdomen. i 78 THE CLASS OF INSECTS. In (lie Coal-beds of New BrunsAvick and Nova Scotia, sev- eral interesting Myriopodous, Neuroptcrous" and OrthopteroLis insects have been fonnd : among them a Cockroach, Archimulacris Acadica (PI. 1,* fig. 2). In Europe, Car- , __^ boniferous insects have been discovered at .-„-'- TVettin, Saarbriick, etc. ^ *^ '-' The insects from these two formations ■^^^ show a tendency to assume gigantic and strange shapes. Tliey are also compre- Fig. C8. he7isive types ^ combining the characters of different families and even different suborders. The most re- markable instance is the Encjereon Boeclivgii Dohrn, from the Coal Formation of Germany. It has been referred by Dr. Hagen, with some doubt, to the Hemiptera, from its long im- mense rostrum into which all the month-parts are produced, the labium ensheathing them as usual in the Hemiptera. Its fore- legs are large and raptorial ; but the filiform many-jointed an- tennae, and the net-veined wings are Neuropterovis characters. Hence Dohrn considers it as a comprehensive type uniting * EXPLANATION OF PLATE 1. Fig. 1. Miamia Bronsonii. A Neuroptcrous insect founcl in iron-stone concre- tions in the Carboniferous beds at Morris, Illinois. The ligure is magnified one- third, and has all its parts restored; the dotted lines indicate the parts not existing on the stone. Reduced from a ligure in the Memoirs of the Boston Society of Nat- ural History, Vol. I. Fig. 2. Archimulacris Acadica. Wing of a Cockroach observed by Mr. Barnes in the coal-formation of Nova Scotia. Fig. o. Platephemera antiqua. A gigantic May-fly obtained by Mr. Hartt in the Devonian rocks of New Brunswick. Fig. 4. Xylobius sigillaricp.. The Myriopod (or Gally-wonn) found in the coal- formation of Nova Scotia, by J. W. Dawson. Copied from a figure in Dr.Dawson's Air-breathers of the Coal-period. Magnified. Fig. .5. Litkentomtim Hartii. A Neuroptcrous insect, the specimen first dis- covered by Mr. Hartt in the Devonian rocks of New Brunswick. This fossil, and those accompanying it, arc the oldest insect-remains in the world. Fig. 0. Three facets from the eye of an insect, considered by Dr. Dawson a Dragon-fly. It was found in coprolites of reptiles in the rocks containing the My- riopod, represented in Fig. 4. Copied from Dr. Dawson's figure, greatly magnified. Fig. 7. Uomothetns fonsili.t. A Neuroptcrous insect from the Devonian rocks of New Brunswick ; it was discovered by Mr. Hartt. Fig. 8. flaplnphlebmm Barnesii. A curious Neuroptcrous insect, of lai'ge size, probably allied to our May-flies; taken by Mr. Barnes from the coal of Cape Bre- ton. These figures, with the exception of 1, 4, and 6, are of life size, and borrowed from tiic new edition of Dr. Dawson's Acadian Geology. Plate 1. Fig. I Fig. i. Fig .2. Fig. 5. Fig. 6. Fig. 7. Fig. 8. OSSIL INSECTS GEOLOGICAL DISTRIBUTION. 70 the characters of the " Neuroptera and Hemiptera. It is a large insect, spreading about two inches ; its body must have measured over an inch in length. In the Mesozoic rocks, the celebrated Solenhofen localit}- in Bavaria is rich in Liassic insect-remains. Dr. Hagen (Ento- mologist's Annual, London, 1862) strAes that among the Solen- hofen fossils the Neuroptera and Orthoptera are most largely represented ; as out of four hundred and fifty species of insects, one hundred and fifty are Neuroptera, of which one hundred and thirty-six are Dragon-flies, and besides "there is a Cory- dalns, one CJirysopa, a large Apochrysa., and a beautiful Nymjyhes. The last two genera, which do not seem very remote from Chrysojjct, are now found onl}' in the Southern Hemi- sphere, NymjyJies is peculiarly an Australian genus." The Lias of England is very rich in fossil insects, especiall}- the Purbeck and Rhoetic Beds (see Brodie's Work on Fos- sil Insects and also Westwood in the Geological Journal, etc. Vol. X.). In the Trias, or New-Red Sandstone of the Connecticut Valley, Professor Hitchcock has found numerous remains of the larva of an aquatic Coleopterous insect. The insects of the Tertiary formation more closely resemble those of the present day. The most celebrated European localit}- is Qilningen in Switzerland. According to Professor O. Heer, over five thousand specimens of fossil insects have been found at Q^^ningen, comprising 844 species, of which 518 are Coleopterous. From all Tertiary Europe there are 1,322 species, as follows : 16G Hymenoptera, 18 Lepidoptera, 166 Diptera, 660 Coleoptera, 217 Hemiptera. 39 Orthoptera, and 56 Neuroptera. "If we inquire to what insect-fauna of the present period the Tertiary fauna is most analogous, we shall be surprised to find that most of the species belong to genera actually found iii the old and the new world. The insect-fauna of OEningen con- tains 180 genera of this category', of which 114 belong to the Coleoptera. Of these last, two (Dineutes and Caryborus) re- main in Europe, while all the others are now found living both in Europe and in America. The whole number of Coleopterous genera furnished by CEningen, and known to me, amount to 80 THE CLASS OF INSECTS. 158 ; those that are common to l)otli hemispheres forming then more than two-thirds of the whole number, while of the actual Coleopterous fauna of Europe, according to the calculation of M. Lacordaire, there is only one-third. The genera found to-day in both parts of the world have then during the Tertiary epoch played a more important part than is the case now ; hence the knowledge of the character of the fauna is rendered more difficult. We find at Qi^ningen but a ver\^ small numl)er (live) of genera exclusively European ; seventeen are ibund to-day in Europe, in Asia, and in Africa, but not in America. For the most part tliey belong to the Mediterranean launa (comprising eight genera) and give to the insect-fauna of Q^ningen a strong proportion of Mediterranean forms. In this fauna I onl}- know of one exclusively Asiatic genus ; two are peculiar to Africa, and two others {AnopUtes and Naupactus) are American. "There are noAV living, however, in Europe certain genen; which, without being exclusively American, since they are found in Asia and in Africa, belong more peculiarly to America ; such are Belostonmm, Hypselonotus, Diplonychns, Evagnrus, /Sten- opoda^ Plecia, Caryborus, and Dineutes. . . . The genera peculiar to our fauna of Tertiary insects amonnt to forty-four, of wliich twenty-one belong to the Coleoptera ; among the Orthoptera there is one, and six Hymenoptera, six Diptera, and eleven Hemiptcra. They comprise 140 species." (Heer.) An apparently still richer locality for Tertiary insects has lieen discovered by Professor Denton west of the Rocky IMoun- tains, near the junction of the White and Green Rivers, Colo- rado. According to Mr. Scudder "between sixty and seventy species of insects were brought home, representing nearly all the ditierent suborders ; about two-thirds of the species were Flies, — some of them the perfect insect, others the maggot-like larvae, — but, in no instance, did both imago and larva of the same insect occur. The greater part of the beetles were quite small ; there were three or four kinds of Homoptera (allied to the tree-hoppers), Ants of two different genera, and a poorly preserved Moth. Perhaps a minute Tlirij^s, belonging to a group which has never been found fossil in any part of the world, is of the greatest interest." He thus sums up what is known of American fossil insects. THE DISEASES OF INSECTS. 81 "The species of fossil insects now known from North America, number eighty-one : six of these belong to the Devonian, nine- to the Carboniferous, one to the Triassic, and sixty-tivc to the Tertiary epochs. The Hymenoptera, Ilomoptera, and Diptora occur only in tlie Tertiaries ; the same is true of the Lcpido})- tera, if we exclude the Morris specimen, and of tlie Colcoptora, with one Triassic exception. The Orthoptcra and Myriopods are restricted to the Carboniferous, while the Neuroptera occur both in the Devonian and Carboniferous formations." Mr. Scudder describes from the Carboniferous formation of Nova, Scotia, besides Xylobms sigillarice Daws., four additional spe- cies (X. similis, fractns and Dawsoni, and Archhdus xylohio- ides, n. g. and sp,), forming the family Archhdiclcc. The Diseases of Insects have attracted but little atten- tion. They are so far as known mostly the result of the attacks of parasitic plants and animals, though epidemics are known to break out and carry off myriads of insects. Dr. Shimer gives an account of an epidemic among the Chinch bugs, which ••was at its maximum during the moist warm weather that fol- lowed the CvVl rains of June and the first part of July, 1SG5/' Species of microscopic plants luxuriate in infinitesimal for- ests within the alimentary canal of some wood-devouring insects, and certain fungi attack those species Avhich are exposed to dampness, and already enfeebled by other causes. Among the true entoYthyta ^ or parasitic plants, whicli do not liowever ordi- narily occasion the death of their host. Professor Leidy describes Enterobryns eJegans^ E. t^j^iraJis, E. alteniatus, Arthromit-iiH rristahis, Cladophytnm comatum^ and CorynocJadns radiafHS, which live mostly- attached to the mucous walls of the interior of the intestine of Jnhis marginatus and two other species of Jtdus, and Passaivs cornidus. Eccrina lovga Leidy, lives in Polydesmns Virgiviensis ; and E. monUiformis Leid}' in P. i/ramdatits. But there are parasitic fungi that are largely destructive to their hosts. Such are Spliaeria and Isaria. "-These fungi grow Avith gi-eat rapidity within the body of the animal they attack, not only at the expense of the nutJi^itive fluids of the latter, but, aft^-r its death, all the interiar soft tissues api)ear 82 THE CLASS OF INSECTS. to be converted into one or more aerial receptacles of spores." (Leidy.) These fungi, so often infesting caterpillars, are hence called "caterpillar fungi." They fill the whole body, distend- ing even the legs, and throw out long filaments, sometimes longer than the larva itself, giving a grotesque appearance to the insect. Leidy has found a species which is very common in the Seventeen-year Locust, Cicada septendecim. He found "among myriads of the imago between twelve and twenty specimens, which, though living, had the posterior third of the abdominal contents converted into a dry, powdery, ochreous- yellow, compact mass of sporuloid bodies." He thinks this Cicada is very .subject to the attacks of these fungi, and that the spores enter the anal and genital passages more readily than the mouth ; thus accounting for their development in the abdomen. The most formidable disease is the '•'• Muscardine" caused by a fungus, the Botrytus Bassiana of Balsamo. It is well known that this disease has greatly reduced the silk crop in Europe. Balbiani has detected the spores of this fungus in the eggs of Bombyx mori as well as in the diflTerent parts of the body of the insect in all stages of growth. Extreme cleanliness and care against contagion must be observed in its prevention. Among plants a disease like Muscardine, due to the presence of a minute fungus {Mucor ')ueUit.o2)horns), fills the stomach of some insects, including the Honey-bee, with its colorless spores, and greatly weakens those affected. Another fungus, Sporendonema muscoi, infests the common House-fly. Another Silk-worm disease called '■'■ Pebrine" carries off many silk-worms. Whether it is of pathological or vegetable origin is not yet settled. V\ There are also a few intestinal worms known to be para- sitic in insects. The well-known "Hair-worm" (Gordins) in its young state lives within the body of various insects in- cluding the Spiders. The tadpole-like young difliers greatly from the parent, being short, sac-like, ending in a tail. Upon leaving the egg they work their way into the body of insects, and there live on the fatty substance of their hosts, where they undergo their metamorphosis into the adult hair-like worm, and make their way to the pools of water in which they live THE DEFORMITIES OF nSTSECTS. 83 and beget their species, and lay "millions of eggs connected together in long cords." Leidy tlins writes regarding the habits of a species which infests grasshoppers. "The number of Gordii in each insect varies from one to five, their length from three inches to a foot ; they occupy a position in the visceral cavity, where they lie coiled among the viscera, and often extend from the end of the abdomen forward through the thorax even into tlie head ; their bulk and weight are fre- quently greater than all the soft parts, including the muscles, of their living habitation. Nevertheless, with this relatively immense mass of parasites, the insects jump about almost as freely as those not infested. "The worms are milk-white in color, and undivided at the extremities. The females are distended with ova, but I have never observed them extruded. When the bodies of Grass- hoppers, containing these entozoa, are broken and lain upon moist earth, the worms gradually creep out and pass below its surface." Goureau states that Filarla, a somewhat similar worm, in- habits Hibernia hrumata and Vanessa prorsa. (Ann. Ent. Soc, France.) Siebold describes Gordius subbiftircKS which infests th(^ Honey-bee, especially the drones, though it is rather the work- ers, which frequent the pools where the Gordii live, that we would expect to find thus infested. Another entozoan is Mer- niis albicans of Siebold, which is a very slender whitish worm much like Gordius, and about five inches long. It is found in the drone of the honey-bee and in some other insects. Deformities of Insects. Numerous instances of supernume- rary legs and antennse are recorded. The antenniie are some- times double, but more commonly the legs. "Of these As- muss has collected eight examples, and it is remarkable that in six of them the piarts on one side are treble." Newport, from whom we have quoted, states that "the most remarkable ex- ample is that given by Lefebvre of Scarites Pyrachmon in which from a single coxa on the left side of the prosternum two tro- chanters originated. The anterior one, the proper trochanter, supported the true jirothoracic leg ; while the posterior one, in the form of an oblong lanceolate body, attached to the base of 84 THE CLASS OF INSECTS. the first, supported two additional legs equally well formed as the true one." The wings are often partially aborted and deformed ; this is especially noticeal>le in the wings of butterflies and moths. Mr. F. G. Sanborn has described and figured a Aving of a female of JJbdlula luctuosa Burm. (Fig. 69), in which among other deformities '"the ptero- ^'S- 69. stigma is shorter and broader than that of the opposite wing, and is situated about one-eighth of an inch only from the nodus, only one cubital vein occurring between them, instead of fourteen as in the opposite wing." (Proceed- ings of the Boston Society of Natural History, vol. xi, p. 326.) Directions for Collecting and Preserving Insects. Insects differ sexually in that the female generally appears to have one abdominal ring less (one ring disappearing during the semi-pupa state, when the ovipositor is formed), and in l)eing larger, fuller, and duller colored than the males, while the lat- ter often differ in sculpture and onuunentation. In collect- ing, whenever the two sexes are found imited they should be pinned upon the same pin, the male being placed highest. When we take one sex alone, we may feel sure that the other is somewhere in the vicinity ; perhaps while one is flying about so as to be easily captured, the other is hidden under some leaf, or resting on the trunk of some tree near by, which must be examined and every bush in the Aicinity \'igorousl3' beaten l)y the net. Many species rare in most i)laces have a metropolis where they occur in great abundance. During seasons Avhen his favorites are especially abundant the collector should lay up a store against years of scarcity. At no time of the year need the entomologist rest from his labors. In the winter, under the bark of trees and in moss he can find many species, or on trees, etc., detect their eggs, which he can mark for observation in the spring when they hatch out. He need not relax his endeavors day or night. Mothing is night employment. Skunks and toads entomologize at night. Early in the morning, at sunrise, when the dew is still on the leaves, insects are sluggish and easily taken with the hand ; I k COLLECTING AND PRESERVING INSECTS. 85 SO at dusk, when many species ai-e found ^ing, and in the night, the collector will be rewarded with many rarities, many species flying then that hide themselves by day, while many caterpillars leave their retreats to come out and feed, when the lantern can be used with success in searching for them. WoUaston (Entomologist's Annual, 1865) states that sandy districts, especially towards the coast, are at all times prefer- able to clayey ones, but the intermediate soils, such as the loamy soil of swamps and marshes are more productive. Near the sea, insects occur most abundantly beneath pebbles and other objects in grassy spots, or else at the roots of plants. In many places, especially in Alpine tracts, as we have found on tlie summit of Mt. Washington and in Labrador, one has to lie dovi^n and look carefully among the short herbage and in the moss for Coleoptera. The most advantageous places for collecting are gardens and farms, the borders of woods and the banks of streams and ponds. The deep, dense forests, and open, treeless tracts are less prolific in insect life. In winter and early spring the moss on the trunks of trees, when carefully shaken over a newspaper or white cloth, reveal many beetles and Hymenoptera. In the late summer and autumn, toadstools and various fungi and rot- ten fruits attract many insects, and in early spring when the sap is running we have taken rare insects from the stumps of freshly cut hard-wood trees. Wollaston says, " Dead animals, partially-dried bones, as well as the skins of moles and other vermin which are ordinarily hung up in fields are magnificent traps for Coleoptera ; and if any of these be placed around or- chards and inclosures near at home, and be examined every morning, various species of Nitidulce, Silphidce, and other insects of similar habits, are certain to be enticed and cap- tured. "Planks and chippings of wood may be likewise employed as successful agents in alluring a vast number of species which might otherwise escape our notice, and if these be laid down in grassy places, and carefully inverted every now and then with as little violence as possible, many insects will be found adhering beneath them, especiall}- after dew}'- nights and in showery weather. Nor must we omit to urge the importance 86 THE CLASS OF INSECTS. of examining the under sides of stones in the vicinity of ants' nests, in which position, during the spring and summer months, many of tlie rarest of our natiA^e Coleoptera may be occasion- ally procured." Excrementitious matter always contains man}- interesting forms in various stages of growth. The trunks of fallen and decaying trees offer a rich harvest for many wood-boring larvae, especially the Longieorn beetles, and weevils can be found in the spring, in all their stages. Nu- merous carnivorous Coleopterous and Dipterous larvte dwell v.ithin them, and other larvj^e which eat the dust made by the l)orers. The inside of pithy plants like the elder, raspberry, blackberry, and syringa, are inhabited by many of the wild bees, Osmia, Ceratina, and the wood-wasps, Cixibro, Stignuis, etc., the habits of which, with those of their Chalcid and Ich- neumon parasites, otfer endless amusement and study. Ponds and streams shelter a vast throng of insects, and should be diligently dredged with the water-net, and stones and pebbles should be overturned for aquatic beetles, He- miptera, and Dipterous larvae. The various sorts of galls should be collected in spring and autumn and placed in vials or boxes, where they may be rear- ed, and the rafters of out-houses, stone-walls, etc., should be carefully searched for the nests of Mud-wasps. Collecting Ajyparatus. First in importance is the net. This is made by attaching a ring of brass wire to a handle made to slide on a pole six feet long. The net may be a foot in diameter, and the bag itself made of tlnn gauze or mosquito- netting (the finer, lighter, and more durable the better), and should be about twenty inches deep. It should be sewed to a narrow border of cloth placed around the wire. A light net like this can be rapidly turned upon the insect with one hand. The insect is captured by a dexterous twist which also throws the Ijottom over the mouth of the net. The insect should be temporarily held between the thumb and fore-finger of the hand at liberty, and then pinned through the thorax while in the net. The pin can be drawn through the meshes upon opening the net. The beating-net should be made much stouter, with a shal- lower cloth bag and attached to a shorter stick. It is used for beating trees, bushes, and herbage for beetles and Hemiptera COLLECTING AND PRESERVING INSECTS. 87 and various larvje. Its thorough use wc would recommend in the low vegetation on mountains and in meadows. The ivuter- net may l)e either round or of the shape indicated in Fig. 70. The ring should be made of brass, and the shallow net of grass-cloth or coarse millinet. It is used for collecting aqua- tic insects. Various sorts of forceps are indispen- Fig. 70. sable for handling insects. Small delicate narrow-bladed for- ceps with fine sharp points in use by jewellers, and made either of steel or brass, are excellent for handling minute specimens. For larger ones long curved forceps are very con- venient. For pinning insects into boxes the forceps should be stout, the blades blunt and curved at the end so that the insect can be pinned without slanting the forceps much. The ends need to be broad and finely indented by lines so as to firmly hold the pin. "With a little practice the forceps soon take the place of the fingers. They will have to be made to order by a neat workman or surgical-instrument maker. Some persons use the ordinary form of pliers with curved handles, but they should be long and slender. A spring set in to separate the handles Avhen not grasped bj^ the hand is a great convenience. Various pill-boxes, vials, and bottles must always be taken, some containing alcohol or whiske3\ Many collectors use a wide-mouth bottle, containing a sponge saturated with ether, chloroform, or benzine, or bruised laurel leaves, the latter be- ing pounded with a hammer and then cut with scissors into small pieces, which give out exhalations of prussic acid strong enough to kill most small insects. Besides these the collector needs a small box lined with corn-pith, or cork, and small enough to slip into the coat- pocket ; or a larger box carried by a strap. Most moths and small flies can be pinned alive without being pinched (which injures their shape and rubs off" the scales and hairs), and then killed by pouring a little benzine into the bottom of the box. Killing Insects for the Cabinet. Care in killing affects very sensibly the looks of the cabinet. If hastily killed and dis- torted by being pinched, with the scales rubbed oft' and other- wise mangled, the value of such a specimen is diminished 88 THE CLASS OF INSECTS. either for purposes of study or the neat appearance of the col- lection. Besides the vapor of ether, chloroform, and benzine, the fumes of sulphur readily kill insects. Large specimens may be killed by inserting a pin dipped in a strong solution of ox- alic acid. An excellent collecting bottle is made by putting into a wide-mouth bottle two or three small pieces of cyanide of potassium, which may be covered with cotton, about half- filling the bottle. The cotton may be covered with paper lightly attached to the glass and pierced with pin-holes ; this keeps the insect from being lost in the bottle. For Diptera, Loevv recommends moistening the bottom of the collecting box with creosote. This is excellent for small flies and moths, as the mouth of the bottle can be placed over the insect while at rest ; the insect flies up into the bottle and is immediately suffocated. A bottle well prepared will, according to Laboulbene, last several months, even a 3^ear, and is vastly superior to the old means of using ether or chloroform. He states, ''the incon- venience of taking small insects from a net is well known, as the most valuable ones usually escape ; but b^' placing the end of the net, filled with insects, in a wide-mouthed bottle, and putting in the cork for a few minutes, the}' will be suffocated." Plnnincf Insects. The pin should be inserted through the thorax of most insects. The Coleoptera, however, should be pinned through the right wing-cover ; many Hemiptera are best pinned through the scutellum. The specimens should all be pinned at an equal height, so that about one-fourth of the pin should project above the insect. The best pins are those made in Berlin by Klager. They are of five sizes. No. 1 beiug the smallest; Nos. 1, 2, and o are the most convenient. For very minute insects still smaller pins are made. A very good but too short pin is made by Edles- ton and Williams, Crown Court, Cheapside, London. Their Nos. 19 and 20 may be used to impale minute insects upou, and then stuck through a bit of cork, or pith, through which a No. 5 Klager pin may be thrust. Then the insect is kept out of the reach of devouring insects. Still smaller pins are made by cutting off' bits of very fine silvered wire at the right length, which may be thrust by the forceps into a piece of pith, after the insects have been impaled upon them. COLLECTING AND PRESERVING INSECTS. 89 Small insects, especially beetles, may be mounted on cards or pieces of mica through which the pin may be thrust. The French use small oblong bits of mica, with the posterior half covered with green paper on which the number may be placed. The insect may be gummed on the clear part, the two sexes to- gether. The under side can be seen through the thin mica. Others prefer triangular pieces of card, across the end of which the insect may be gummed, so that nearly the whole un^ der side is visible. Mr. WoUaston advocates gumming small Coleoptera upon cards. Instead of cutting the i)ieces of cards first, he gums them promiscuously upon a sheet of card-board. ''Having gummed thickly a space on your card-board equal to, at least, the entire specimen when expanded, place the beetle upon it, drag out the limbs with a pin, and, leaving it to dry, go on with the next one that presents itself. As the card has to be cut after- wards around your insect (so as to suit it), there is no advan- tage in gumming it precisely straigJd upon your frame, — though it is true that a certain amount of care in this respect lessens your after labor of cutting-off very materially. When j-our frame has been filled, and you are desirous of separating the species, cut out the insect with finely pointed scissors." For mending broken insects, i. e. gumming on legs and an- tenna which have fallen off, inspissated ox-gall, softened with a little water, is the best gum. For gumming insects upon cards Mr. WoUaston recommends a gum "composed of three parts of tragacanth to one of Arabic, both in powder ; to be mixed in water containing a grain of corrosive sublimate, without which it will not keep, until of a consistency just thick enough to run. As this gum is of an extremely' absorbent nature, nearly a fortnight is required before it can be properly made. The best plan is to keep add- ing a little water (and stirring it) every few days until it is of the proper consistency. It is advisable to dissolve the grain of corrosive sublimate in the water which is poured Jirst upon the gum." Preservative Fluids. The best for common use is alco- hol, diluted with a little water ; or whiskey, as alcohol of full strength is too strong for caterpillars, etc., since it shrivels them 90 THE CLASS OF INSECTS. up. Glycerine is excellent for preserving the colors of cater- pillars, though the internal parts deca^^ somewhat, and the specimen is apt to fall to pieces on being roughly handled. Laboulbene recommends for the preservation of insects in a fresh state plunging them in a preservative fluid consisting of alcohol with an excess of arsenious acid in fragments, or the common white arsenic of commerce. A pint and a half of al- cohol will take about fourteen grains (tro}') of arsenic. The living insect, put into this preparation, absorbs about jo^oo of its own weight. When soaked in this liquor and dried, it will be safe from the ravages of Moths, Anthrenus, or Dermestes. This liquid will not change the colors of blue, green, or red beetles if dried after soaking from twelve to twenty-four hours. He- miptera and Orthoptera can be treated in the same wa}'. A stay of a month in this arseniated alcohol mineralizes the insect, so that it appears very hard, and, after drying, becomes glazed with a white deposit which can, however, be washed off" witli ale(,>hul. In this state the specimens become too hard for dissection and study, but will do for cabinet specimens designed for permanent exliibition. Another preparation recommended b}' Laboulbene is alcohol containing a varialjle quantity of corrosive sublimate, but the latter has to be weighed, as the alcohol evaporates easily, the liquor becoming stronger as it gets older. The strongest solu- tion is one part of corrosive sublimate to one hundred of alco- hol ; the weakest and best is one-tenth of a part of corrosive sublimate to one hundred parts of alcohol. Insects need not re- main in this solution more than two hours before drying. Both of these preparations are veiy poisonous and should be handled with care. Tlie last-named solution preserves specimens from mould, which will attack pinned insects during damp summers. A very strong brine will preserve insects until a better liquor can be procured. Professor A. E. Verrill recommends two sim- ple and cheap solutions for preserving, among other specimens, the larvte of insects "with their natural color and form remark- ably perfect." Tlie first consists of two and a half pounds of common salt and four ounces of nitre dissohed in a gallon of water, and filtered. Specimens should be i)repared for i)erma- nent preservation in this solution by being previously immersed i COLLECTIXG AND PRESERVING INSECTS. 91 ill a solution consisting of a quart of the first solution and two ounces of arseniate of potash and a gallon of water. (Pro- ceedings Boston Societ)'^ Nat. Hist., vol. x, p. 257.) The nests, cocoons, and chrysalids of insects niaj^ be pre- served from injury from other insects b^' being soaked in the arseniated alcohol, or dipi)ed into benzine, or a solution of car- bolic acid or creosote. Preparing Insects for the Cabinet. Dried insects niaj'^ be moistened by laying them for twelve or twenty-four hours in a box containing a layer of wet sand, covered with one thick- ness of soft paper. Their wings can then be easily spread. Setting-boards for spreading the wings of insects ma3' be made ))y sawing deep grooves in a thick board, and placing a strip of pith or cork at the bottom. The groove may be dee]) enough to allow a quarter of the length of the pin to project above the insect. The setting-board usually consists of tliiu parallel strips of board, leaving a groove between them wide enough tc receive the body of the insect, at the bottom of which a strip of cork or pith should be glued. The ends of the strips should be nailed on to a stouter strip of wood, raising the surface of the setting-board an inch and a half so that the pins can stick through without touching. Several setting-boards can be made to form shelves in a frame covered with wire gauze, so that the specimens may be preserved from dust and destructive in- sects, while the air may at the same time have constant access to them. The surface of the board should incline a little to- wards the groove for the reception of the insect, as the wings often gather a little moisture, relax and fall down after the insect is dried. Moths of medium size should remain two or three days on the setting-board, while the larger thick-bodied Sphinges and Bovibycidce require a week to dry. The Avings can be arranged by means of a needle stuck into a handle of wood. They should be set horizontally, and the front mar- gin of the fore-wings drawn a little forward of a line perpen- dicular to the body, so as to free the inner margin of the hind wings from the body, that their form may be distinctly seen. When thus arranged, they can be confined by pieces of card pinned to the board as indicated in figure 71, or, as we prefer, by square pieces of glass laid upon them. 92 THE CLASS OF INSECTS. After the insects have been thoroughly dried they should not be placed in the cabinet until after having been in quarantine; to see that no eggs of Dermestes or Anthrenus, etc., have been deposited on them. For preserving dried insects in the cabinet Laboulbiine recommends plac- ing a rare insect (if a beetle or any Fig. 71. other hard insect) in water for an hour until the tissues be softened. If soiled, an insect can be cleansed under water with a fine hair-pencil, then submit it to a bath of arseniated alcohol, or, better, alcohol with corrosiA'c sublimate. If the insect becomes prune-colored, it should be washed in pure alcohol several times. This method will do for the rarest insects ; the more common ones can be softened on wet sand, and then the immersion in the arseniated alcohol suffices. After an immersion of an hour or a quarter of an liour, according to the size of the insect, the pin is not affected by the corrosive sulilimate, but it is better to unpin the insect previous to immersion, and then pin it when almost dry. For cleaning insects ether or benzine is excellent, applied with a hair-pencil ; though care should be taken in using these substances which are very inflannnable. After the specimens are placed in the cabinet, they should be farther protected from destructive insects l:)}^ placing in the drawers or boxes pieces of camphor wrapped in paj^er perfo- rated by pin-holes, or bottles containing sponges saturated with benzine. The collection should be carefull}" examined ever^^ month ; the presence of insects can be detected by the dust lieneath them. Where a collection is much infested with destructive insects, benzine should be poured into the bottom of the box or drawer, when the fumes and contact of the ben- zine with their bodies will kill tliem. The specimens them- selves should not be soaked in the benzine if possible, as it renders them brittle. Insed-cahinet. For permanent exhibition, a cabinet of shal- low drawers, protected by doors, is most useful. A drawer may be eighteen by twenty inches square, and two inches deep in the clear, and provided with a tight glass cover. For constant COLLECTING AND PRESERVING INSECTS, 93 use, boxes made of thin, well-seasoned wood, with tight-fitting covers, are indispensable. P'or Coleoptera, Dr. Leconte recom- mends that they be twelve by nine inches (inside measurement). For the larger Lepidoptera a little larger box is preferable. Others prefer boxes made in the form of books, wliich may be put away like books on the shelves of the cabinet, tliough the cover of the box is apt to be in the way. The boxes and drawers should be lined with cork cut into thin slips for soles ; such slips come from the cork-cutter about twelve by four inches square, and an eighth of an inch thick. A less expensive substitute is paper stretched ui)on a frame. Mr. E. S. Morse has given in the American Naturalist (vol. I, p. 156) a plan which is very neat and useful for lining boxes in ;; large museum, and which are placed in horizontal show-cases (Fig. 72). "A box is made of the re- quired depth, and a light frame is fitted to its in- terior. Upon the upper and under surfaces of this frame, a sheet of white paper (drawing or log- paper answers the pur- pose) is securely glued. rig. 72. The paper, having been previously dampened, in drying con- tracts and tightens like a drum-head. The frame is then secured about one-fourth of an inch from the bottom of the box, and the pin is forced down througli the tliicknesses of paper, and if the bottom of the box be of soft pine, the point of the pin may be slightly forced into it. It is thus firmly held at two or three different points, and all lateral movements arc prevented. Other advantages are secured by this arrangement besides firmness ; Avhen the box needs cleaning or fumigation, the entire collection may be removed by taking out the frame, or camphor, tobacco, or other material can be placed on the bottom of the box, and concealed from sight. The annexed figure represents a transverse section of a portion of the side and bottom of the box with the frame. A, A, box ; B, frame ; 94 THE CLASS OF INSECTS. P, P, upper and under sheets of paper ; C, space between lower sheet of paper and liottoni of box." Other substitutes are the pith of various plants, especially of corn ; and palm wood, and "inodorous felt" is used, beinij; cut to fit the bottom of the box. Leconte recommends that "for the purpose of distinguish- ing specimens from different regions, little disks of vai'iousl^' colored paper be used ; they are easily made by a small punch, and should be kept in wooden pill-boxes ready for use ; at the same time a key to the colors, showing the regions em- braced by each, should be made on the fly-leaf of the catalogue of the collection." He also strongly recommends that the "specimens should all be pinned at the same height, since the ease of recognizing species allied in characters is greatly in- creased by having them on the same level." He also states that "it is better, even when numbers with reference to a catalogue are employed, that the name of each species should be A\Titten on a label attached to the first speci- men. Thus the eye is familiarized with the association of the species and its name, memory is aided, and greater power given of identifying species when the cabinet is not at hand." For indicating the sexes the astronomical sign ^ (Mars) is used for the male, and 9 (Venus) for the female, and 9 for the worker. Transportation of Insects. While travelling, all hard-bodied insects, comprising many Hymenoptera, the Coleoptera, Hc- miptera, and many Neuroptera should be thrown, with their larvjfi, etc., into bottles and vials filled with strong alcohol. "VVlien the bottle is filled new liquor should be poured in, and the old may be saved for collecting purposes ; in this way the specimens will not soften and can be preserved indefinitely, and the colors do not, in most cases, change. Leconte states that "if the bottles are in danger of being broken, the specimens, after remaining for a day or two in alcohol, may be taken out, partially dried by exposure to the air, but not so as to be brit- tle, and these packed in layers in small boxes between soft paper ; the boxes should then be carefully closed with gum- paper or paste, so as to exclude all enemies." Lepidoptera and Dragon-flies and other soft-bodied insects ma}- be well preserved by placing them in square pieces of pa- REARING LARV^. 93 per folded into a triangular form with the edges overlapping. Put up thus, multitudes can be packed away in tin boxes, and will bear transportation to any distance. In tropical climates, chests lined with tin should be made to contain the insect- boxes, which can thus be preserved against the ravages of white ants, etc. In sending live larvae by mail, they should be inclosed in lit- tle tin boxes, and in sending dry specimens, the box should be light and strong, and directions given at the post-otHce to stamp the box lightly. In sending boxes by express they should be carefully packed in a larger box, having an inter- space of two inches, which can be filled in tightly with hay or crumpled bits of paper. Beetles can be wrapped in pieces of soft paper. Labels for alcoholic specimens should consist of parchment with the locality, date of capture, and name of collector wi'itten in ink. A temporary label of firm paper with the locality, etc., written with a pencil, will last for several years. Preservation of Larvce. Alcoholic specimens of insects, in all stages of growth, are very useful. Few collections contain al- coholic specimens of the adult insect. This is a mistake. Many of the most important characters are effaced during the drying process, and for purposes of general study alcoholic speci- mens, even of Bees, Lepidoptera, Diptera, and Dragon-flies arc; very necessary. Larvce, generally, may be well preserved in vials or bottles of alcohol. They should first be piit into whiskey, and then into alcohol. If placed in the latter first, they shrivel and become distorted. Mr. E. Burgess preserves caterpillars witli the colors unchanged, by immersing them in boiling water thirty or forty seconds, and then placing them in ecjual pai'ts of alcohol and water. It is well to collect larvffi and pupne indiscriminatel}', even if we do not know their adult forms ; wo can approximate to them, and in some cases tell very exactly what they must be. Rearing Larv^. More attention has been paid to rearing Caterpillars than the j'^oung of any other suborder of insects, and the following remarks apply more particularly to them, but 96 THE CLASS OF INSECTS. very much the same methods may be pursued in rearing the larviB of Beetles, Flies, and Hymenoptera. Subterranean larvjii have to be kept in moist earth, aquatic larva? must be reared in aquaria, and carnivorous larvse must be supplied with flesh. The larvae of Butterflies are rare ; those of moths occur more frequently, while their imagos may be scarce. In some years many larvfe, which are usually rare, occur in abundance, and should then be reared in numbers. In hunting for caterpillars bushes should be shaken and beaten over newspapers or sheets, or an umbrella ; herbage should be swept, and trees examined carefulh^ for leaf-rollers and miners. The best specimens of moths and butterflies are obtained by rearing them from the egg, or from the larva or pupa. In confinement the food should be kept fresh, and the box well ventilated. Tumblers covered with gauze, pasteboard boxes pierced with holes and fitted with glass in the covers, or large glass-jars, are very convenient to use as cages. The bot- tom of such vessels may be covered with moist sand, in which the food-plant of the larva may be stuck and kept fresh for several days. Larger and more airy boxes, a foot square, with the sides of gauze, and fitted with a door, through which a bot- tle of water may be introduced, serve well. The object is to keep the food-plant fresh, the air cool, the lai-va out of the sun, and in fact everything in sucli a state of ecjuilibrium that the larva will not feel the change of circumstances Avhen kept in confinement. Most caterpillars change to pnpte in the autumn ; and those which transform in the earth should be covered with earth, kept damp by wet moss, and placed in the cellar until the following summer. The collector in seeking for larva? should carry a good number of pill-boxes, and especially a close tin box, in which the leaves may be kept fresh for a long time. The different forms and markings of caterpillars should be noted, and they should be drawn carefully together with a leaf of the food-plant, and the drawings and pupa skins, and per- fect insect, be numbered to correspond. Descriptions of cat- erpillars cannot be too carefully made, or too long. The relative size of the head, its ornamentation, the stripes and spots of the body, and the position and number of tubercles, and the hairs, or fascicles of hairs, or spines and spinules. ENTOMOLOGICAL WORKS. 97 fs'hifh arise from Ihem, should be noted, besides the general form of the body. The lines along the body are called dorsal., if in the middle of the back, subdorsal; if upon one side, lat- eralf and ventral when on the sides and under surface, or stig- matal if including the stigmata or breatliing pores, which are generally parti-colored. Indeed, the whole biography of an insect should be ascertained by the observer ; the points to be noted are : 1. Date, when and how the eggs are laid ; and number, size,, and marking of the eggs. 2. Date of hatching, the appearance, food-plant of larva, and number of daj-s between each moulting ; the changes the larva undergoes, which are often remarkable, especially before the last moulting, with drawings illustrative of these ; the hab- its of the larva, whether solitary or gregarious, Avhether a day or night feeder ; the Ichneumon parasites, and their mode of attack. Specimens of larvjie in the different moultings should be preserved in alcohol. The appearance of the larvae when full-fed, the date, number of days before pupating, the forma- tion and description of the cocoon, the duration of larvae in the cocoon before pupation, their appearance just before changing, their appearance while changing, and alcoholic specimens of larvfc in the act, should all be studied and noted. 3. Date of pupation ; description of the pupa or chrysalis ; duration of the pupa state, habits, etc. ; together with alcoholic specimens, or pinned dry ones. Lepidopterous pupte should be looked for late in the summer or in the fall and spring, about the roots of trees, and kept moist in mould until the imago appears. Man}' Coleopterous puptxi may also occur in mould, and if aquatic, under submerged sticks and stones, and those of borers under the bark of decaying trees. 4. Date when the insect escapes from the pupa, and method of escape ; duration of life of the imago ; and the number of broods in a season. Entomological Works. The titles of a few of the most im- portant works on Insects are given below. The more advanced student should, however, possess Dr. Hagen's Bibliotheca En- tomologica, 8vo, 2 vols., Leipzig, 1862-3, which contains a 7 98 THE CLASS OF INSECTS. complete list of all entomological publications up to the year 1H62. Besides these he should consult the annual reports on the progress of Entomology published in Wiegmann's Archiv fur Naturgeschichte, begun in 1834, and continued up to the present time ; and also GiJnther's Zoological Record (8vo, Van Voorst, London), beginning with the jear 18G4. Occasional articles are also scattered through the various government re- ports, and those of agricultural societies and agricultural paperso GENERAL WORKS. The •works of /^wammerdnm, Malphn/hi, Leemcenhoel-, Lyonnct, Senses, Meckel, linwdolir, Suckow, Merian, and Herbst. Hennmur, lidnv Ant. de. Memoires pour servir ii I'llistoire des Insectes. Paris, 1731 -1742, 7 vols. 4to. Jtoesel, Ai(f/. Joh. Der monatlich herausgegeben Insekten-Belustigxing'. Niirnberg', 1740-1701, 4 vols. 4to, illustrated. Geer, Carl de. Memoires jiour servir a I'Histoiro des Insectes, 1752-1778, 7 toIs. 4to. T.innmis, Corolus. Systema Natura^, 173.'). 12th edition, 1766-1768. Fabricius, Joh. Christ. Systema Entomologiae, 1775, 8vo. . Genera Insectorum. 1777, Svo. ■ . Species Insectorum, 1781, 2 vols. Svo. . Mantissa Insectorum, 1787, 2 vols. Svo. . Entomologia Systematica^ 4 vols. Svo, 1702-94. Cramer, P. Papillons exotiques des trois parties dii monde. 4 vols. 4to, 177.1-82. Stall, Cnsper. Supplement to Cramer's Papillons exotiques. 4to, Amsterdam, 1787-01. Smith, .T. E., and Abbot, .lalin. The Natural History of the Rarer Lcpidopterou.< Insects of Georgia. Fol. Plates. London, ]7'.>7. Latreille, Pierre Andre. Precis des cai'acteres generique des Insectes, 1790, Svo, . (J^nera Crustaccorum et Insectorum, 4 vols. Svo, 1S0(!-1809. . Consideration generales sur 1' Ordre natural des Animaux compo.'-ant les Classes des Crustaces, des Arachnides et des Insectes. . In Cuvier's Piegne animal, Svo, ISIO. . Families naturelles du Regne animal, Svo, 1S25. . Cours d' Entomologie, Svo, 1831. Fahricitia, Otkn. Fauna Grocnlaudica. Hafnia>, 17S0 Svo. Contains Libelhila virgo (erroneously), riiryganea rhombica, Termes dirivntoriiim, etc. Drunj, Drew. . Illustrations of Natural History, etc. London, 1770-1782. 4to,3 vols. (ed. Westwood, 1S37). Numerous si)ecies are figured and described. Treviranus, G. 11. Vermischte Schriften anatoniischen und physiologischen Inhalts Bd. 1 u. 2. Gottingen. 1810-17, 4to. Jfac Leay, W. S. Woyx Entomologies, 2 vols. London, 1810. Meifjen, F. W. Systematische Beschreibung der bekannten europiiischen zweiflii- geligen Insecten. 7 vols. Aachen and Hanim, 1S1S-1S35. (Although this work contains only European species, many of them are common to both continents.) Say, T. American Entomology. 3 vols. AVith plates. Philadelphia, 1824, 25, 28. . Complete Writings on the Entomology of North America, edited by J. L. Leconte, M.D. 2 vols. Svo, colored plates. New York, 1859, Jiaer, K. E. v. Beitrage zur Kentniss der niederen Thiere. (Extracted from Nova Acta Acad. Leopold. Carolin. xiii. 2, 1827.) ENTOMOLOGICAL WORKS. 99 Palisot de Bemn-aix, A. J. Inseotes recueillis on Afrique et en Anuirique, clnns Ics royaumes d' Owarc et de Benin, a Saint-Domingue et dans les Etats-Unis, pen- dant les annees, 17S6-!)7. Fol. with 90 plates, Paris, 1805-21. Saviffi))/, J. C. tie. Description de P Egypte. Histoire natnrelle. Crustace-s, Araehnides, Myriapodes et Insectes, 53 pi. in gv. fol. Paris, 1S09-1838. Ex- plication sonimaire des planches pai'J. V. Aiidouin, Paris, 1820, lol. Curtis, John. Description of the Insects brought home by Commander James Clark. Ross's .Second Voyage. App. Nat. Hist., 18.'51,4to, plates. (Several Arctic species are described.) Kirby, W. 7. Stainton, H. T. The Natural History of the Tineina. Svo, with many plates. Lon don, vols. 1-8, 18,5.>-G4, Svo. Lacordaire, J. T. Genera des Coleopteres. Svo, tomes 1-7. Paris, Roret, 18.54. Doisduval, J. A. Histoire generale et Iconographie des Lepido)>tercs et des Che- nilles de I'Amerique septentrionale. Svo. Paris, Roret, 1829-42. Species generale des Lepidopteres. Svo. Roret, Pans, 185G. , Essai sur 1' Entomologie horticole. Svo. Paris, 18(17. Practical Entomologist. Entomological Society of Philadelphia. Vols. 1, 2, 4to, 180.5-07. Harris, T. W. A Treatise on some of the Insects of New England, Avhich are injurious to Vegetation. Third edition, illustrated. Boston, 1802. Leconte, J. L. Classification of the Coleoptera of North America. Part I, 1801-2. Smithsonian Institution. . List of Coleoptera of North America. Svo, lSG;3-(). Smithsonian Institu- tion. . New Species of North American Coleoptera. Svo. Part 1, 1803-0. Smith- sonian Institution. . Coleoptera of Kansas and Eastern New Mexico. 4to. 3 plates. ia5fl. Smithsonian Institution. Hagen, H. Synopsis of the Neuroptera of North America. Svo. 1801. Smith- sonian Institution. Morris, J. G. Catalogue of the described Lepidoptera of North America. Svo 1800. Smithsonian Institution. ENTOMOLOGICAL WORKS. 101 Osten Sncl-cn, R. Catalogue of the described Diptera of North America. 1858. Smithsonian Institution. Loew, H., and Osten Sucken, R. Monograph of tlie Diptera of North America. Parts 1,2, 8vo, 18(;'2-(i4. Smithsonian Institution. Trimble, I. P. A Treatise on the Insect Enemies of Fruit and Fruit Trees. The Curculio and Apple moth. 4to. Plates. New York, 18(55. MORPHOLOGY. Savigny, J. C. Memoires sur les Animaux sans Vertebres. 1 Partie. De.ecriptioa et Classilication des Auimaux invertebres et articules, 1. Fascicide. Theorie des Organes de la Bouche des Crustacea et des Insectcs. Paris, 18Ui. Audoidn, J. ]'. llecherches anatomiqucs sur le Thorax des animaux articules et celui des Insectes hexapodes en particulier. (Aunales d. Scieuc. natur. 1, 1824, J). 'J7 and 410.) Eschscholtz, J. F. Beschreibung des inneren Skeletes einiger Insekten aus vcr- schiedeneu Ordnungen. Dorpat, 1820, 8v'0, ]). 24-49, 2 Taf. Baer, K. E. V. Ueber das aussere und innere Skelet (Meckel's Archiv. f. Anatom. u. Physiol. 182(i, p. 327-374). Erichson, IF. F. Ueber zoiilogische Charaktere der Insekten, Arachniden und Crustaceen. (Entoniographien, S. 1-28.) Berlin, 1840, 8vo. BrtdU, A. llecherches sur les Transformations des Appendices dans les Arti- cules (Annales des Sciences naturelles, 3. ser. II, 1844, p. 271-374). Leuckart, R. Ueber die Morphologie und die Verwandtschaitsverhaltnisse der Wirbellosen Thiere. Braunschweig, 1848, 8vo. ANATOMY AND PHYSIOLOGY. Straus-Dilrcldieim, 11. Considerations generales sur P Anatomic comparee des Animaux articules, anxquelles on a joint 1' Anatomic descriptive du Melolontha vulgaris. Paris, 1828, 4to. 10 pi. Diifour, L. Numerous anatomical papers in the Annales des Sciences naturelles, I'aris. Siehold, C. Th.v. Lehrbuch der Vergleichenden Anatomic der wii-bcllosen Thiere. Berlin, 1848, 8vo. Translated by W. I. Burnett. Boston, 18.51, 8vo. Gegenhdtir, C. Grundziige der vergleichenden Anatomic. Leipzig, 18.")9, 8vo. Geoffroy St. Hilmre, Efieiuie. Considerations philosoiihiqnes sur la determination du Systfeme solide et du Systeme nerveux des Annnanx articules. (Annal. d. scienc. natur. II, 1824, p. 20.j flf., Ill, p. 11)9 u. p. 4.53 ff.) Newport, G. On the Structure, Relations, and Development of the nervous and circulatory Systems, an. Journal of the Academy of Natural Sciences, Philadelphia. Commenced 1817. 7V«nAY(c;. nerets) often present. No metamorphosis, . . J Sxh-dass TTLBocly cylindrical, worm-like. Segments "j not grouped into regions. Head free ; eyes sim- j Myiuopoda pie; antennae present; wingless; numerous ab- '> cceutipedes") dominal legs present; yelk-sac present for a | *^ ^ ■'' short period after hatching. No metamorphosis. J The Orders of Six-footed Insects f (Hexapoda). Metahola. The body usually cylindrical; prothorax 'j small; mouth-parts moi-e generally haustellate | Hymexoptera (formed for sucking) ; metamorphosis complete ; )■ Lkpidopteka. pupa inactive ; larva usually cylindrical, very | Dipteua. unlike the adult, J leterometabola. The body usually flattened ; pro- S Coleoptera. thorax large and squarish ; month-parts usually | Hemiptera. adapted for biting ; metamorphosis in a large )■ Orthoptera. number incomplete; pupa often inactive; larva Neuroptera. flattened, often resembling the adult, . . J Thysanuka. * The number of wingless forms is comparatively few. The Diptera have but one pair. tTlic so-called "cephalothorax" of Spiders is not like that region in the Crabs, the head being much Ireer from tlie thorax. X Leuckart's classification is an advance on others in his considering the Hexa- poda, Arachnida, and Myriapoda as orders instead of classes, but he says nothing { { GROUPING OF INSECTS. 105 The following diagram shows, in a rude way, the relative rank and affinities of the eight orders, and of the two series of Six-footed Insects. Neuroptera. TLysanura, Through JOej^isma, and Podura which are wingless Thysa- nurous insects, the lower series is connected with the Myriopods, the minute degraded FauropxijS and Scolopendrella perhaps forming tlie connecting links ; and through the wingless flies, Braula, Chionea, and Nycteribia, the Diptera, belonging to the higher series, assume the form of the Spiders, the head being small, and sunken into the thorax, Avhile the legs are long and slender. The first and highest series culminates in Ajns, the Plonej^-bee ; and the second, or lower, in Cicindela, the Tiger-beetle. regarding the rank and value of the minor jrroups. Professor Agassiz extended Leuckart's views in considering the seven grand divisions of the order of Hexapods as suborders. Inl8(;3 (How to Observe and Collect Insects, Maine Scientific Sur- vey, and Synthetic Types of Insects, Boston Journal of Natural History), we proposed a new classification of these divisions, by which they are thrown into two main groups headed by the Hymcnoptera and Coleoptera respectively. These two groups, as represented in the diagram, are nearly equivalent in value, and stand in a somewhat parallel relation. There is nothing like a linear series in the animal kingdom, but it is like a tree. The hiirher series of orders form more of a linear sei'ies than the lower series, so that in the diagram the Neuroptera, Orthoptera, Ileniiptera, and Coleoptera fonn a more broken series tlian the Hy- menoptei'a, Lepidoptera, and Diptera. A Bee, Butterfly, and House-fly are much more closely allied to each other than a Beetle, a Squash-bug, a Grasshopper, and a Dragon-fly are among themselves. The Neuroptera are the most indepen- dent, and stand at the bottom of and between the two series, though by the Orthou- tera they arc very intimately linked with the Hemiptera and Coleoptera. 106 THE CLASS OF INSECTS. o o a n o m O Pi o 02 W < : I d i5 t^ « 5 a"" §"2 ^3^-^ ^j-^:.^« ^ ^XZi<^l O :J, jT ^ cf rt o ? S « o g = < ~ I •r- s: O O £ ,^ S 5 y 5 ic-drt =, 3 o s •2 'T — -c t-^ cT N S3 -!; ;3 ^ i S 2 o J3 3 3* ■^ o •X ~ E s o 1 x — in ~ ^ 'w)'^ 3 9r '^ =^ G ^. S -i-'x ci ^ ~? 2~ =J P I S5 s'»^ ;2; X H 5^ <<3 « .2 O 'B ^-' ^ — l^ r- i o ~ p,^ t« -w O S CO lc r — ' " 3 do S 6 o 3 - ■ ~ 0.2 i: 'CD ^ 2 : o i ^ 11 o .3 ^ s -t^ -3 = ? rf •'~^'^ ^^ ' "' ' a S S J « . • '^ 3 . CO .s cr„ ij - "-^ J ?. J ^ *=^ § o ^ c| =i rt i : 6 ^ a B ^6 3 a X Spa - o o p- S S-^^ c S r^ _ O •- ~ i ;i O ^ -^ S '~ a a ■!=? O "o 3 c? ^ ^j.a* =-2 OJ o e 5^ a3| ^ii COS Qh-S a- ^ .o ■3 I 2 -^ 00 ^ = HYMENOPTERA. 107 HYMENOPTERA. The Bees, Wasps, Saw-flies, Ants, and other members of this suborder differ from all other insects in having, in the higlier and more typical forms, the basal joint of the abdomen thrown for- ward upon and intimatel}' united with the thorax. The head is large, Avith large compound eyes, and three ocelli. The mouth-parts are well developed both for biting, and feeding on the sweets of plants, the ligula especially, used in lapping- nectar, being greatly developed. The other regions of the body are more distinct than in other insects ; the wings are small but powerful, with comparatively few and somewhat irregular veins, adapted for powerful and long-sustained flights ; and the genital appendages retracted, except in the Ichneu- mon parasites and Saw-flies, within the body, are in the female modified into a sting. The transformations of this suborder are the most complete of all insects ; the larvaa in their general form are more unlike the adult insects than in any other suborder, while the pupa^, on the other hand, most clearly approximate to the imago. The larvae are short, cjdindrical, footless (excepting the young of the Saw-flies, the lowest family, which are provided with abdominal legs like Lepidopterous larvae), worm-like grubs, which are helpless, and have to be fed by the prevision of the parent. The pupa has the limbs free, and is generally contained' in a thin silken cocoon ; that of the Saw-flies, however, being thick. The Hymenoptera exhibit, according to Professor Dana, the normal size of the insect-type. "This archet^pie size is be- NOTE to page 100.— Ray divided the Hexapods into Coleopfera and Aneloptern, the latter division embracing all the other suborders except the Coleoptera. His Ametamorphota Hexajwda contained the wingless hexapoda; wliile the Avietamor- plwta polypoda comprise the Myriopods, and the A. octopoda the Arachnids. Lin- naeus' Aptera (with numerous feet) are equivalent to the I\Iyriopods,and his Aptera (with S-14 feet) to the Arachnids. In Fabricius' system the Klentheratn are equiva- lent to the Coleoptera ; the i7/o«a<« to the Orthoptera ; the Synisinta to the "Seurop- tera; the I'iezata to the Hymenoptera; the Odonata to the Libeliulidaj; the Olossata to the Lepidoptera; the lihyngota to the Hemiptera; the Antliata to the Diptera. The Mitosnta are the Myriopods, and the Unogata, the Arachnids. In Latreille's system the Suctorin, or Fleas, are now referred to the Diptera; ihe Parasita or Lice, to the Hemiptera, and the Thijsanura to the Xeuroptera. 108 HYIVIENOPTERA. tween eight and twelve lines (or twelfths of an inch) in length, and two and a half and tlu'ee lines in breadth." This size is probably a smaller average than in any other snborder ; thus the Hymenoptera while being tlie most cephalized, consequently comprise the most compactly moulded insectean forms. Besides these structural characters, as animals, endowed with instincts and a kind of reason differing, perhaps, onJn in degree from that of man, these insects outrank all other Articu- lates. In the unusual differentiation of the individual into males and females, and, generally sterile workers, with a farther dimor- phism of tliese three sexual forms, such as Huber has noticed in the Humble-bee, and a consequent subdivision of labor among them ; in dwelling in large colonies, thus involving new and intricate relations with other insects (such as Apliides, ant-hill-inhabiting beetles, and the peculiar bee-parasites) ; their wonderful instincts, their living principally on the sweets and pollen of flowers, and not being essentially carnivorous {i.e. seizing their prey like the Tiger-beetle) in their habits, as are a large proportion of the other suborders, with the exception of Lepidoptera ; and in their relation to man as a domestic an- imal, subservient to his wants, — the Bees, and Hymenoptera in general, possess a combination of characters which are not found existing in any other suborder of insects, and which rank them first and highest in the insect series. The body-wall of the H3'menoptera is unusually dense and hard, smooth and highly polished, and either naked, or covered Avith hair as in a large proportion of the bees. The head is large, not much smaller than the thorax, and its front is verti- cal. The antenuffi are short, filiform, often geniculate, very rarely pectinated. The mandibles are large, stout, toothed, and the maxilhie are well developed into their three subdivisions, the palpi being usually six-jointed ; the labial palj^i are usually four-jointed, and the prolongation of the under lip, or ligula, is highl}' developed, being furnished with a secondarj^ pair of palpi, the paraglossia, while in the pollen-gathering species the ligula is of great length, and thus answers much the same purpose as the spiral tongue (maxilla?) of the Lepidoptera. Reaumur states that the Bee does not suck up the liquid sweets, but laps them up with its long slender hairy tongue. HYMENOPTERA. 109 "Even in the drop of honey the bee bends tlie end of its tongue about, and lengthens and shortens it successively, and, indeed, withdraws it from moment to moment." The liquid passes along the upper surface of the pilose tongue, which is withdrawn between its sheaths, the palpi and maxilhe, and thus ''conveys and deposits the liquid with which it is charged within a sort of channel, formed by the upper surface of the tongue and the sheaths which fold over it, by which the liquid is conveyed to the mouth." (Shnckard.) The thorax forms a rounded compact oval mass, Avith the prothorax and metathorax A-ery small, the mesothorax being large, and also the propodeum, to which the pedicel of the ab- domen is attached. The pleurites are large and bulging, while the sternum is minute. The coxjie and trochantines are large, and quite free from the thorax ; and the trochanters are small, while the rather slender legs are subject to great modifications, as they are devoted to so many different uses by these insects ; thus, in the Sand-wasps they are strongly bristled for the purpose of digging, and in the Bees, the basal joint of the tarsi is much enlarged for carrying pollen. "The manner in which the bee conveys either the pollen, or other material it purposes carrying home, to the posterior legs, or venter, wdiich is to bear it, is very curious. The rapidity of the motion of its legs is then verj^ great ; so great, indeed, as to make it very difficult to follow them ; but it seems first to collect its material gradually with its mandibles,- from which the anterior tarsi gather it, and that on each side passes successively the grains of which it consists to the inter- mediate legs, by multiplicated scrapings and twistings of the limbs ; this, then, passes it on by similar manoeuvres, and de- posits it, according to the nature of the bee, upon the pos- terior tibiiB and tarsi, or upon the under side of the abdomen. The evidence of this process is speedily manifested by the pos- terior legs gradually exhibiting an increasing pellet of pollen. Thus, for this purpose, all the legs of the bees are more or less covered with hair. It is the mandibles which are chiefly used in their boring or excavating operations, applying their hands, or anterior tarsi, only to clear their way ; but by the construc- tive, or artisan bees, they are used both in their building and 110 HYMENOPTEE A . mining operations, and are worked like trowels to collect moist clay, and to apply it to the masonry of their habitations." (Shuckard.) The four wings are present, except in rare instances. They are small ; the hinder pair long, narrow, ovate, lanceolate. The costal edge of the fore-wing (Fig. 29), is generally straight, becoming a little curved towards the apex, which is obtusely subrectangular ; the outer edge is bent at right angles, while the inner edge of the wing is long and straight. The veins are often difficult to trace, as in the outer half of the wing they break up into a system of net-veins, which are few in number, yet the continuations of the subcostal, median, and submedian veins can be distinguished after careful study. In some low Ichneuvioniclce, the Proctotrujiidce, and Chalcididce, the veins show a tendency to become obsolete, only the simple subcostal vein remaining ; and in Pteratomus, the veins are entirely obliterated, and tlie linear feather-like wings are in one pair fissured, reminding us of the Plume- moths, Pteropiiorus. The abdomen is composed in the larva state of ten segments, but in the adult stinging Hymenoptera, of six complete seg- ments in the females, and seven in the males ; while in the lower families the niunber varies, having in the Tenth redi- nidce, eight tergites on the upper side and six sternites on the lower side. The remaining segments are, during the transfor- mations of the insect, aborted and withdrawn within the body. The ovipositor and corresponding parts in the male have been described on pp. 14-18. The nervous system consists in the larvre of eleven ganglia, in the adult five or six of these remain as abdominal ganglia, while the remainder, excluding the cephalic ganglia, are placed in two groups in the thorax. The cerebral ganglia are well developed, evincing the high intellectual qualities necessary in presiding over organs with such different uses as the simple and compound eyes, the antennje, and lingua and palpi, and mandibles, especially in those sociable species which build complete nests. The digestive system, in those bees which sip up their food, consists, besides the external mouth-parts, of a "long a;soph- HYMENOPTERA . 1 1 1 agus which dilates into a thin-walled sucking stomach," whicli in the Aj^icirice and Vesjiidce may be simply a lateral fold, or, as in many Crabronidce, "attached solely by a short and narrow peduncle." In Formica, Cynij)s, Leucospis, and Xyphid- rla there is a globular uncurved callous gizzard, which is en- veloped by the base of the stomach, according to Siebold, who also states that "those Hjmenoptera which are engaged during a long and active life in labors for the raising and support of their j'oung, have a pretty long and flexuous stomach and in- testine, and the first has, usually, many constrictions ; " while the Cynipidoi, Ichneximonidce, and Tenthredinidce , which take no care of their young, have only a short small stomach and intestine. The salivary glands consist of two rather short ramified tufts, often contained entirely in the head. The tracheae consist, as in other insects, of two main branches, from which numerous transverse anastomosing branches are given off, with numerous vesicular dilatations. Two such vesi- cles of immense volume are situated at the base of the abdo- men, which according to Hunter and Newport "serve chiefly to enable the insect to alter its specific gravity at pleasure dur- ing flight, and thus diminish the muscular exertion required during these movements." The urinary vessels are ver^- numerous in the H3-mcnoptera ; they are usually short and surround the pylorus in numbers of from twenty to one hundred and fifty. The two poison glands (Fig. 54, 7i,g) are composed of long ramose tubes, resembling the salivary glands in their minute structure. The poison is poured from these into a pyriform sac lodged near the base of the sting, which is provided with a peculiar muscular apparatus for its sudden extension and with- drawal. The poison, in the Ants, Bees, and Wasps, consists, according to Will, of "formic acid, and a whitish, fatty, sharp residuum, the former being the poisonous substance." (Bur- nett.) The wax-secreting apparatus consists of special dermal glands, as Milne-Edwards supposed. Clans has shown (see Gegenbaur's Verg. Anatomic) that these minute glands are mostly unicellular, the external opening being through a fine chitinous tube on the outer surface of the inteaiument. In the? 112 HY31ENOPTERA. wax-producing insects these glands are developed in great numbers over certain portions of the body. In the Aphides, whose bodies are covered with a powder consisting of fine waxy threads, tliese glands are collected in groups. Modifications of them appear in the Coccidoe. In the wax-producing Hymen- optera the apparatus is somewhat complicated. The bees secrete wax in thin, transparent, membranous plates on the under side of the abdominal segments. Polygonal areas are formed by the openings of an extraordinarily large number of fine pore-canals, in which, surrounded by very numerous tra- cheal branches, the cylindrical gland-cells are densely piled upon each other. These form the wax organs, over which a fatty layer spreads. In those bees which do not produce wax, the glands of the wax organs are slightly developed. AVax organs also occur in the Humble bees. The honey is elaborated by an unknown chemical process, from the food contained in the proventriculus, or crop, and which is regurgitated into the honey-cells. The ovaries consist of many-chambered, four, six, or a hun- dred, short tubes. "The receptacida seminis is nearly always simple, round or ovoid, and necked, and is prolonged into a usually- short seminal duct." The glandula appendicidaris con- sists of a bifurcate tube which opens into the ductus semincdis, and only rarely into the capsida semincdis itself. In the Tenthredinidce , " this apparatus is formed on a different type ; the seminal vesicle is a simple diverticulum of the vagina, and more or less distinct from it, besides it is defi- cient in the accessory gland. The copulatory pouch is absent in all the Ilymenoptera, as are also the sebaceous glands with those females which have a sting and a poison gland," while in other insects the sebaceous glands are present, and it would be nat- urally inferred, therefore, that the two are homologous, but modified for diverse functions. The two testes of the male are "composed of long follicles, fasciculate and surrounded, together Avith a portion of the torose deferent canal, by a common envelope ; but more com- monly the two testes are contained in a capsule situated on the median line of the body." (Siebold.) The eggs are usually long, cylindrical, and slightly curved in HYMENOPTER A . 113 the Bees ; in the Wasps they are more globular, and aff.xed by tlieir smaller somewhat pedicelled end to the side, near the bot- tom of the cell in which they are laid. The eggs of the lower families tend to assume a spherical form. The eggs of (lif- erent species of Bomhus present no appreciable differences. The larvre of the Bees and Wasps, especially the social species, which live surrounded by their food, are of a very persistent form, the various genera differing but slightly, while the species can scarcely be separated. Such we have found to be the case in the Bees and Wasps ( Vespidcc) and Fossorial Wasps. The sexes of the species with a ver}- thin tegument, such as Apis^ Bomhns^ and Vespa^ can be quite easily distin- guished, as the rudiments of the genital armor can be seen through. The Hymenoptera are mostl}' confined to the warmer and temperate regions of the earth ; as we approach the poles, the Bees disappear, with the exception of Bomhus, and perhaps its parasite Apathns ; a species of Vespa is found on the Lab- rador coast, which has a. climate like that of Greenland. No fossorial species of Wasps are known to us to occur in the arc- tic regions, while a few species of Ants, and several Chalcidi- (Ue and Ichneumonidce are not uncommon in Northern Labrador and Greenland. Our alpine summits, particularly that of Mt. AVashington, reproduces the features of Northern Labrador and Greenland as regards its Ilj^menopterous fauna. The tropics are, however, the home of the Hymenoptera, and especially of the Bees. There are estimated to be about twenty-five thousand living species of this suborder, and this is probably a much smaller mimber than are yet to be discovered. In geological history, the Hymenoptera do not date far back compared with the Neuroptera and Orthoptera, and even the C'Oleoptera. Indeed they were among the last to- appear upon the earth's surface. The lower forms, so far as the scanty records show, appeared first In the Jura formation : the Ants appear in the Tertiarj^ period, especially in amber. As we have noticed before, the Hymenoptera are more purely terrestrial than any other insects. None are known to Ix- aquatic in the early stages, and only two genera have beeu.found 8 114 IIYMEXOPTERA. swimming in the adult state on the surface of pools, and they arc the low, minute, degraded Proctotrupids, Prestioicliia nutans and Polynema nutans descrilied by Mr. Lubbock. The Hymenoptera do not imitate or mimic the forms of other in- sects, but, on the contrary, their forms are extensively copied in the Lepidoptera, and especiall}^ the Diptera. A partial excei)- tion to this law is seen in the antenna of the Australian genus Thaivmutosonia, where they are long and slender, and knobbed as in the butterfly, and also in Tetralonia mirahilis of Smitii. from Brazil. The Hymenoptera, also, show tlieir superiority to all other in- sects in the form of their degraded wingless species, such as Pezomachus, the workers of Formica and the female of MutiUu . In these forms we have no striking resemblances to lower orders and suborders, but a strong adherence to their own Hymenop- terous characters. Again ; in the degradational winged forms, we rarely find the antenniB pectinated ; a common occurrence in the lower suborders. In a low species of the Apiari'a' , LamjrrocoUetes ckidocerus, from Australia, — that land of anom- alies, — the antennre are pectinated. This, ]Mr. F. Smith, the. best living authority on tliis suborder, says, "is certainly the most remarkal)le bee that I have seen, and the only in- stance, to my knowledge, of a bee having pectinated antennae ; such an occurrence, indeed, in the Aculeate Hjaiienoptera is only known in two or three instances, as \n Psam mother ma fluh- dlata amongst the Mutillidce, and again in Ctenocerics Klvrjii in the Pomjiilidw, ; there is also a modification of it in one or two other species of Po7npilidce ." Among the Tenthre- dinidoi, the male Lojyhynis has well-pectinated antennoe, as also has Cladomacra macropus of Smith, from New Guine;i and Celebes. The wings of perhaps the most degraded Hymenoptera, the Proe^o^rM^x'dfl', are rarely fissured ; when this occurs, as in Pteratomus Patnamii, they somewhat resemble those of F*tero- 2^hor)is, tlie lowest moth. It is extremely rare that the com- l)ound eyes are replaced by stemmata, or simple eyes ; in but one instance, the genus AnthopJtorubia., are the eyes in the male sex reduced to a simple ocellus. This species lives in the darkness of the cells of Anthophora. APIARI^. 115 By reason of the permanence of the type, due to the high rank of these insects, the generic and specific characters arc founded on A'ery slight differences, so that these insects, and particuh^rly the two higher families, the Wasps ( Vespidce) and Bees {Apiarice) are the most difficult insects to study. The easiest characters for the recognition of the genera, lie in th(? A'enation of the wings j though in the fossorial families the legs vary greatly. The best specific characters lie in the sculptur- ing and style of coloration, but the spots and markings are apt to vary greatly. The great differences between the sexes ar(i liable to mislead the student, and hence large collections arc indispensable for their proper study. Bees act as "marriage ]niests" in the fertilization of plants, conveying pollen from flower, to flower, and thus insuring the formation of the fruit. It is said that many plants could not be fertilized without the interposition of Bees. Their interesting habits deserve long and patient study ; it is for their observations on the insects of this suborder that the names of Reaumur, the two Hubers, and Latreille will be ever held in special remembrance. Most Hymenoptera love the sun, and they may be caught Avhile flying about flowers. The nests of bees, wasps, and ants should be sought for and the entire colony captured, together with the parasites. The hairy species should be pinned while in the }iet, and the naked ones can be put in the collecting-bot- tle. The larger species may be pinned, like other insects, through the thorax ; but the minute Chalcids, etc., should be gummed, like small Coleoptera, upon cards. The nests of bees and of wasps and ants and the young in various stages of growth should be collected, and in such num- bers as to show their different stages of construction, to serve as illustrations of insect architecture. ApiarivE Latreille (Apidce Leach). This and those families succeeding which are provided with a true sting, were called b}'' Latreille Hymenojjtera Acideata. The male antennae are mostly thirteen-jointed, while in the female they are twelve- jointed. The females (and the workers, when they exist) feed the larvae, which mostly live in nests or cells. 116 HYMEXOPTERA. In the social Bees, besides the normal male and female forms, there are asexual females, whose inner genital organs are parti}- al)orted, though externally only differing in their smaller size from the true females. The male antennae are longer, tapering more towards the tips, and the eyes of the male approach each other closer over the vertex than in the opposite sex, though these are characters which apply to other Hymenoptera. The mouth-parts are in the higher genera greatly elongated, the labium being long, with the lingua of great length, and the lobes of the maxilhe long and knife-shaped ; but these parts, as well as the form of the jaws, are subject to great modificatioiis in the dilferent genera : the labial palpi are four-jointed, and the maxillary palpi are from one to six-jointed. The hind tibia and basal joint of the tarsi are, in the pollen-gathering species, A'ery broad ; the tibia is in Apis and Bombus hollowed on the outside, and stiff bristles project over the cavity from each side of the joint, forming the honey-basket (corbiciibim), on which the "clodden masses of honey and pollen" are con- veyed to their nests. In the parasitic genera, such as Apathus^ the tibia is, on the contrary, con\ex, rather than concave, though of the usual width ; while in Homada, also parasitic, the legs are narrow, the tibia not being dilated. In Andrena and its allies, Ilalktns and CoJletes, the niouth- l»arts, especially the tongue, are much shortened, thus atfbrd- ing a passage into the VesjiidcB . In these genera the tongue is folded back but once between the horny encasement of the maxilla?, but in the higher Ai^iaricp the part formed by the union of the lingua and maxilla is twice bent back, and thus protected by the horny lobes of the maxillie. The fore-wings have two or three subcostal (cubital) cells. There are two thousand species of this famil}-. The differ- ences between the larvt^ of the various genera of this family are very slight, those of the parasitic species are, however, readily distinguished from their hosts. The higher Apiarice, comprising the subfamily ^4j:i/»rt, have the ligula long, cylindrical, while the labial palpi have two very long, slender, compressed basal joints, and two short terminal joints. The genus AjJi's has no terminal spurs on the hind tibiae, APIARI^. 117 while the fore-wings have three subcostal (cubital) cells, the middle of which is elongated and acutel}' wedge-shaped. The eyes in the male are united above ; the mouth-parts are nearly aborted, and the hind legs are smootli. In the female there are two paragiossffi on the ligula, and the maxillary palpi are one-jointed. The worker only ditfers externally from the female in the shorter abdomen. The larva of the Honey-bee closely resembles that of Bom- bus, but the body is shorter, broader, and more flattened, while the head is less prominent, and the lateral tubercles along the bod}' are, perhaps, less prominent than in the young Humble- bee, otherwise the two genera are, in the larval state, much alike. In its natural position, the larva lies at the bottom of the cell doubled upon itself. Though the larvae are said usually to feed upon pollen, Mr. Desborough states that honey alone is the food of the grub, as he reared 729 larvjB with no other food than honey. But as with the wild bees they ma}' extract honey from the pollen provided for them. He says the matured bees ma}' be observed feeding at night on the bee-broad (pollen). Lang- stroth (The Hive and Honey-bee), however, states that "pol- len is indispensable to the nourishment of the young. It is very rich in the nitrogenous substances which are not contained in the honey." The Honey-bee, Apis meUifica^ is now distributed over the civilized world. It was introduced into this country during the seventeenth century, and into South America in 1845 (Ger- staecker). The Italian, or Ligurian, bee is considered by F Smith as being a climatic variety. The cultivation of the Honey-bee is rapidly increasing in this country, but the German Bee-masters have made the most pro- gress in theoretical and practical Bee-culture. Convenient hives are now constructed by which all the operations of the bees can be observed at leisure. Gerstivcker thus sums up the habits of the Honey-bee : A fertilized queen which, with a few workers, has wintered over, lays its eggs in the spring first in the worker, and afterwards, at a later period, in the drone- cells (both arranged in two perpendicular rows of cells). Early in summer, the workers construct the larger flask- shaped queen- 118 IIY.MEXOPTERA. cells, Avhicli are placed on the edge of the comb, and in these tlie queen-larvie are fed with rich and choice nourishment. As soon as tlie first of the new brood of queens is exclud('d from its cell, which it indicates by a peculiar buzzing noise, the old queen deserts the nest, carrying away with her a part of the 3warm, and thus forms a new colonj^ The recently excluded queen then lakes its marriage flight high in the air witli a drone, and on its return undertakes the management of the hive, and the duty of laying eggs. When another queen is disclosed, the same process of forming a new colon}- goes on. "VViien the suppl}' of young queens is exhausted, the workers fall upon the drones and destroy them without mercy. The first brood of Avorkers live about six weeks in suuuner, and then give way to a new brood. Mr. J. G. Desborough states tliat the maximum period of the life of a Avorker is eight months. The queens are known to live five years, and during their whole life lay more than a million eggs (V. Berlepseh). Langstroth states that "during the height of the breeding season, she will often, under favorable circumstances, lay from 2,000 to 0,000 eggs a day." According to Von Siebold's discovery only the queens' and Avorkers' eggs are fertilized by sperm- cells stored in the receptaculum seminis, and these she can fertilize at Avill, retaining the power for four or five year's, as the muscles guarding the duct leading from this sperm-bag are subject to her Avill. Drone eggs are laid by unfertilized queen-bees, and in some cases even by Avorker-bees. This last fact has been confirmed by the more recent observations of Mr. Tegetmeier, of London. Principal Leitch, according to Tegetmeier. has suggested the theor}' that a Avorker egg may develop a queen, if transferred into a queen-cell. "It is well known that bees, depri\'ed of their queen, select scA'eral worker-eggs, or very young larA'je, for the purpose of rearing queens. The cells in Avhieh these eggs are situated are lengthened out and the end turned doAvn- ward." He suggests that the de\'elopment into a queen Avas caused by the increased temperature of the queen-cell, above that of the AA'orker-cells. But Messrs. F. Smith and Woodbury (Proceedings of the Entomological Society of London, January 2, 1862) support F. APIARIiE. 119 Ruber's theory, that the change is due to '-the quality as well as quantity of food with which the royal larxa is supplied," though Dr. Leitch objects, that it has been by no means con- clusively proved " that the so-called royal jelly differs in anv respect from the ordinary food supplied to the worker larva ; " and Mr. Woodbury cites the ex})eriments of Dzierzon, as (juoted by Kleine, "that as Huber, by introducing some ro\nl jelly in cells containing Avorker-brood, obtained queens, it may be possible to induce bees to construct royal cells, when the Apiarian prefers to have them, by inserting a small portion of royal jelly in cells containing worker-larvre." Kleine takes "an unsealed royal cell — which usually contains an excess of royal jelly — and removes from it a portion of the jelly, on the point of a knife or pen, and b}- placing it on the inner margin of any worker cell, feels confident that the larvie in them will be reared as queens." Before these points are settled we must study the habits of the Wild Bees, and of the other social Hymenoptera and Whit(> Ants, together with the social Aphides more carefully. Mr. F. W. Putnam pertinently states, "at present I cannot lielieve that the peculiarity of food, or the structure of the cells, pro- duces a difference of development in Humble-bees, for tlie lar- vte, as has been previously stated, were seen to make their own cells from the pollen paste. Is it not more natural to believe, as has been suggested to me by Professor J. Wyman, that the difference in the development of the eggs is owing to their be- ing laid at various times after impregnation? Thus, if I am right in supposing that the queens are impregnated by the males late in the summer, the eggs, laid soon after, produce the large queen larvte ; * the next set of eggs, laid in the spring, produce the workers, or undeveloped females, while from those deposited still later, male bees are principally develo]>ed." (Proceedings of the Essex Institute, Salem, vol. iv, 1«G4, p 103.) Referring to Mr. Putnam's statement that there are both small and large queens (besides the workers). Dr. Gerst{\;cker infers, * Dr. Gerstajcker, on the other hand, states that " from the brood-cells of a nest of liomhus musrorum, found by him on the 18th of September, there were devel- oped at the end of the same month only workers." 120 HYMEXOPTEllA. "from the examination of numerous individuals found %ing in the spring after hibernation, that these could not be considered as true queens, since their ovaries were only moderately devel- oped, though larger than those of the workers, while in the true queen, captured in the summer, the ovaries were perfectly developed. This corresponds almost entirely to what we find in the wasps, whose spring females have only moderately de- veloped ovaries." How the Honey-bee builds its cells, and whether they are ex- actly hexagonal, are questions that have interested the best observers from Maraldi who wrote in 1712, and Reaunun-, whose Memoires appeared in 1740, down to the present date. Their solution involves not only the closest observation of the insect while at work, but also the shrewdest judgment to ex- plain the facts observed and deduce a legitimate theory. Does the bee intelligently plan her work out beforehand, or does she follow the guidance of what is called instinct? Does she construct hexagonal cells which are mathematicall}' exact, or does she vary the proportions of each cell, so that it is per- fect only in its general ideal form? Again, in making the cell, is the bee actually capable of making such a cell alone, or is it due to the resultant action of several bees? Professor J. Wy- man is of the latter opinion, as he thinks "that if left alone to build a single cell, this would most probably be round. In the cells of Melipona, as Huber's plate shows, they are only hex- agonal when in contact with the adjoining cells." (Proceed- ings of the Boston Society of Natural History, x, p. 278. 1866.) A similar view is that proposed in 1862 b}' the Rev. Samuel Ilaughton, in a paper read before the Natural History Society of Dublin, where he says, according to Mr. F. Smith, that the hexagonal form of the cell " may be accounted for simply by the mechanical pressure of the insects against each other during the formation of the cell. In consequence of the instinct that compels them to work with reference to a plane, and of the cylindrical form of the insect's body, the cells must be hex- agonal." Mr. G. R. Waterhouse (Transactions of the Entomological Societ}^ of London. Third series, vol. ii, p. 129, 1864) has APIARI.E. 121 proposed what has been called the ''circular theor}-," or what the author himself terms ''the principle of working in seg- ments of circles." He contends '' that the hexagonal form of the cells of certain bees and wasps may, and does, arise out of this mode of action when under certain conditions ; that those condi- tions are, that the cells are so commenced that their natural cir- cumferences, as the work proceeds, are either simply brought into contact with each other, or that the cells are so placed that the (we will say theoretical) circumferences must intersect. Contact with adjoining cells, then, is an essential condition to bring about the hexagonal form as I have before pointed out (See Proceedings of the Entomological Society, 1858, p. 17) ; but for this result it is not necessary that a hexagonal cell should be completely surrounded by other cells." Is not this theor}', after all, too mechanical ? Is not our bee more of a free agent? Does it not have a mind to design its work? Mr. F. Smith, who has devoted years to the study of Hymenoptera, especiall}' the higher forms of this suborder, the Bees and AVasps, replies to both theories of Waterhouse and Haughton, b}' bringing in the case of the Wasps which also build hexagonal cells, showing that a solitary wasp will build its cells in very regular hexagons. Thus the nest of the soli- tary Wasp, Icaria guttatlpennis^ "consists of a double row, the number of cells being ten ; I now direct j^our attention to the fact that all the cells are perfectly hexagonal, the exterior planes being as beautifulty finished as those in contact with the inner planes of the opposing cells. I have placed a draw- ing of this nest (Plate 5, Fig. 7) in the box on the table, and I ])articularly wish you to observe, that the first cell is carried up in a perfectly hexagonal form above the adjoining cells ; a proof that, if Wasps never build perfect isolated hexagonal cells, they certainl}' possess the capability of doing so.^ The exterior of all the cells, as I before observed, is hexagonal, not cjdindri- cal, until fresh cells are added on the outer side, as was ob- served to be the case in combs of the Hive-bee, by Mr. Tegetmeier." (Proceedings of the Entomological Society of London. Third series, ii, 18G4, p. 135.) An examination of the cells of three species of PoUstes (the female of which begins alone in the spring to build her nest 122 HYMENOPTERA. the cells of which are afterwards greatly increased in numljcr after the first brood of females appear) , convinced us that the Wasp begins with the circular cup-shaped form of cell, and when about depositing an egg in it, changes her mode of ope- rating, builds up the edges into a hexagonal form, and carries up the rim of each cell independently to its required height. She thus apparently changes her plan at a certain stage of the work, and is so far a free agent. Mr. Smith also exhibited a portion of the nest of another wasp, Tatua Morio (Plate 5, Fig. 9), that proved to his mind the primary intention of the wasp instinctively to build cells with exactly six sides. The figure represents part of one of the flat floors, on which the foundations of the cells are laid in regular hexagons, instead of beginning in hemispherical cups. Mr. Smith (p. 141) concludes, "that all hexagonal cells are not constructed upon a circular principle, and that the primary idea of all social bees and wasps is not to produce cylindrical fells with hemispherical bases." In this connection the following extract from Mr. Smith's lemarks is of interest : "It may not be known that in order to expedite the building of honey-combs, it is a common i)ractice with bee-keepers in Germany to furnish hives with artificial foundations for the cells ; these consist of sheets of wax, upon which is impressed a series of pyramidal hollows ; in fact, the counterpart of a comb built by the bees themselves, entirely deprived of the cell-walls ; and it is from such a piece of comb that the casts for the artificial foundations are obtained. A piece of casting of this description I la}^ before 3'ou, and I par- ticularly call your attention (addressing the members of the P^lntomological Society of London) to the commencement of the outer cells ; you will see, in some instances, a single plane of the hexagonal cell commenced, in others two or three are in progress ; here you have a ground-plan supplied, or, I may say, the foundations of the habrtations ready prepared, upon which the laborers are to raise the walls, and you may see how admi- rably they have done it. Instinct enables the bee to construct hexagonal cells without teaching, and, we are told, in one un- deviating manner. Surely the example before us exhibits an amount of intelligence on the part of the bees in availing them- APiAPJ.i-:. 123 selves of such adventitious aid. Must we not henceforth, when speaking of the marvels of the hive or the vespiary, erase from our vocabulary such terms as blind instinct ; and must we not cease to stigmatize the bee as a mere machine ? " At the meeting of the same society held Feb. 1, 1864, Mr. F. Smith exhibited a collection of Wasps' nests, — one of Vesjxi rufa, the rest of V. vulgaris; they were in various stages of formation, the earliest consisting of only a single cup contain- ing the first egg, others consisting of three or four cups, whilst others again were more complete. The whole had been arti- ficially obtained by Mr. Stone, who tempted the wasps to build by excavating holes in banks and furnishing them with foot- stalks ; in fact, Mr. Stone appeared to possess the power of inducing wasps to build nests of almost an}' shape he pleased. But to return to the cell of the Bee. It should first be proved that the cells are not exactly and mathematically per- fect hexagons, though sufficiently so for the purpose for whicii they are used. In the Proceedings of the American Academy of Arts and Sciences, vol. vii, 1866, Professor Wyman has, by a most careful as well as novel and ingenious mode of investiga- tion, proved that the cells are all more or less imperfect, and that a hexagonal cell mathematically exact, does not exist in nature, but only in theor}'. The form of the cell is liable to marked variations, chief among which the following may be mentioned, in the author's own words : "1. The diameters of workers* cells may so varj', that ten of them ma}' have an aggregate deviation from the normal quantity equal to the diameter of a cell. The average varia- tion is a little less than one half that amount, namely, nearly 0.10 inch, in the same number of cells. '•2. The width of the sides varies, and this generally in- volves a variation of the angles which adjoining sides make with each other, since the sides vary not only in length but in direction. "3. The variation in the diameters does not depend upon accidental distortion, but upon the manner in which the cell was built. 124 HYMENOPTERA. "4. The relative size of the rhombic faces of the pyramidal base is liable to frequent variation, and this where the cells are not transitional from one kind to another. "5. When a fourth side exists in the basal pyramid, it may be in consequence of irregularity in the size of the cells, or of incorrect alignment of them on the two sides of the comb." Sometimes one of the faces is lost, and a new one formed, so that all the basal portion of the cell becomes reversed, as ABC will be seen by refer- ence to Figs. 73 and 74 ; the first repre- Fig. T.!. senting the cells when the base is viewed, and the second when looked at perpendic- ularly to one of the sides. In both figures A indicates the ordinary foi'm of the cell. The whole a B c series of Fig. 74 shows the gradual introduction of the new face, which is seen on the lower border, and the elimination of one of the original faces, which is seen on the upper border. At L_ B. which is intermediate between the two extremes, the four faces consist of two equal rhombs, — one of which is the outgoing and the other the incoming one, and two equal hexagons. B, Fig. 74, represents the sides of the same cell, which, instead of forming three trapeziums, as at A, a, b, c, now form two pentagons, a' and c', and a parallelogram, b'. At C, Figs. 73 and 74, the forms are in all respects the reverse of those of A. A and C are symmetrical with each other, and B is sj'mmetrical in itself. No pre- cise number of cells is necessary for the purpose of making this transition, for it may take place in two or three, or extend through a long series, as in Fig. 73. "6. Ordinarily, the error of alignment does not amount to more than one or two diameters of a cell. But occasionally a V c Fig. 74. Fig. 7.5. APIARI^. 125 the rows of cells on one side of the comb may deviate from their true direction with regard to those on the other, to the extent of 30°." "Thus, if a piece of normal comb be held in the position in which it was built, two of the opposite angles of the hexagon. Fig. 75, A, a, will be in the same vertical line, and two of the sides will be parallel to this. The same is true of the opposite side of the comb ; and thus all the cor- responding parts of the cells on the two sides will be par- allel. In the deviation we are now noticing, the change is like that represented in A, where the cell a is in its true position, while the cell 5, which is from the oppo- site side, and is in contact with a, varies from it by about 30°. If we look at these two cells in the direc- tion of their sides as at B, the prism a will have one Fig. 76. of its angles towards the e3-e, and b one of its sides. In consequence of this deviation and the continual crossing of the rows on opposite sides, the p^-ramidal base is not made. and the cell is shortened. "7. In curved or bent combs the cells on the concave side tend to be- come narrower, while those on the other tend to become broader to- wards their mouths. In Fig. 7G (this and Figs. 77 and 78 are made ^°' '^" from impressions obtained directly from the comb and transferred to wood ; they represent the form of the cells exactly), as in the central line of cells, there are a variety of hexagons, each resultuig from the union 126 HYMENOPTERA. of two cells, the base being double while the mouth is single. That on the line a, b, has three sides at one end, united by two long sides with one at the other, and thus two of the opposite sides are not parallel ; at c, d, two sides at a b '9 c d c / Fig. 78. either end are united by two long sides, these last being par- allel ; and at Uj)a; Fip:. 3, lai'va. Fij?. 4, Jirmila creca; Fifr. 5, larvii. Fiff. 6, Tri- c.kodes apUiriux : a, hu'v.i ; b, pupa. Fij;. 7, AfeloU anfiunticollM ; Fig. S, freshly hatchetl larva; Fig. 0, second stage of larva; Fig. 10, first stage of .«cmi-pnpa; Fig. 11, luipa. Fig. 12, Sti/lnps Childreui \n the hcjly of a wild bee, Anrlrcna; Fig. 13, top view of the same removed from its host; Fig. 14, male of tlie same; n, side view. Fig. 1.5, yfaror mellitophoru.t, a parasitic fungus. Fig. 115, unknown larva found in nest of Ilumblc-bcc. Descriptions of the insect parasites will be given beyond. Plaio 2 Fig. 1, Fig. 3. Fig. 2. Fig. 5. Fig. 4. Fig. 13, PARASITES OF THE IIO>'EY UEE. APIAKI^. 12i> the spoeies is also confirmatory of the same supposition ; in- deed, the great diversity in tliis respect observable in tliesc bees, ap|)eavs to me to be analogous to a similar diversity in the length of the bills of humming-birds, which, it is Avell known, are always adapted for reaching the nectaries of the particuhir tlowers which they usually frequent." In regard to the immense numbers of individuals in a col- on^', Mr. Stretch, who collected them at Panama, "found a nest several feet in length in the hollow of a tree, containing thousands of individuals, their numbers being, as he informs me, apparently countless. "Gardner, in his travels, gives a list of such species (of Melipona) as he met in the provinces of Piauhy and Goyaz, where he found them numerous ; in every bouse, he says, 'you find the honey of these l)oes ; ' many species, he tells us, build in the hollow trunks of trees, others in banks ; some suspend their nests from branches of trees, whilst one species constructs its nest of clay, it being of large size ; the honey of this spe- cies, he says, is very good." (Smith.) In a nest of Trigona carhonaria from Eastern Australia, Smith, of the British Museum, found from 400 to 500 dead workers crammed in the spaces between the combs, but he did not find a female among them. The combs are arranged precisely similar to those of the common wasp. The number ol" honey-pots, which are placed at the foot of the nest, amounted to 250. Smith inclines to the opinion that the hive of Trigona con- tains several prolific females; '"the accounts given of the mul- titudes inhabiting some nests is too great, I think, to render it possible that one female could produce them all. Mr. Stretch described a hive that he saw, occupying the interior of a decay- ing tree, that measured six feet in length, and the multitude of bees he compared to a black cloud. M. Guerin found six fe- males in a nest of Mdipona fnlvipes.''' Hill states, in Gosse's Naturalist's Sojourn in Jamaica, •'that the wax of these bees [Trigona] is very unctuous and dark colored, but susceptible of being whitened by bleaching. The honey is stored in clusters of cujjs, about the size of 1; igeon's eggs, .at the bottom of the hive, and always from the 9 150 iiymj:,noptera. brood-cells. The brood-cells are hexagonal ; the}' are not deep, and the young ones, when ready to burst their casement, just till t'le whole cavity. Tlie mother bee is lighter in color than the other bees, and elongated at the abdomen to double their length." Smith also states that the female of this genus has the abdomen greatly distended, reminding one of the gravid female of the White Ant. (Smith, Proc. Ent. Soc, London, Dec. 7, 18G3.) In North America, our nearest ally, as regards its habits, of the true Honej'-bee, is the Humble-bee (Bombus), of which over forty species are known to inhabit North America. The economy of the Humble-bee is thus : the queen awakens in earl}' spring from her Avinter's sleep beneath the leaves or moss, or in deserted nests, and selects a nesting-place generally in an abandoned nest of a field-mouse, or beneath a stump or sod, and "immediately," according to Mr. F. W. Putnam, "collects a small amount of pollen mixed with honey, and in this deposits from seven to fourteen eggs, gradually adding to the pollen mass until the first brood is hatched. She does not wait, however, for one brood to be hatched before laying the eggs of another ; but, as soon as food enough has been collected, she lays the eggs for a second. The eggs [Plate 4, Fig. 2] are laid, in contact with each other, in one cavity of the mass of pollen, with a part of which they are slightly covered. They are very soon developed ; in fact, the lines are nowhere dis- tinctly drawn between the egg and the larva, the larva and pupa, and again between the latter and the imago ; a perfect series, showing this gradual transformation of the young to the imago, can be found in almost every nest. "As soon as the larvae are capable of motion and commence feeding, they eat the pollen by which they are surrounded, and, gradually separating, push their way in various directions. Eating as they move, and increasing in size quite rapidly, they soon make large cavities in the pollen mass. When they have attained their full size, they spin a silken wall about them. Avhich is strengthened by the old bees covering it Avith a thin laj-er of wax, Avhich soon becomes hard and tough, thus form- ing a cell. [Plate 4, Figs. 1, 2.] The larvae now gradually attain the pupa stage, and remain inactive until their full devel- Plate 3. J'AKASITES OF M'ILD BEES. APIARI^E. 131 opment. They then cut their way out, and arc ready to assume their duties as workers, small females, males or queens. "It is apparent that the irregular disposition of the cells is due to their being constructed so peculiarly by the larva*. After the first brood, composed of workers, has come forth, the queen bee devotes her time principally to her duties at home, the workers supplying the colony with honey and pollen. As the queen continues prolific, more workers are added, and the nest is rapidly enlarged. "About the middle of summer eggs are deposited which produce both small females and males." . . . "All eggs laid after the last of July produce the large females, or (queens ; and, the males being still in the nest, it is presumed th:,t the queens are impregnated at this time, as, on the approach of cold weather, all except the queens, of Mhich there are several in each nest, die." (Putnam, Com. Essex Inst., vol. iv, p. 98, 1864.) Besides Apathus, the larvae of various moths consume the honey and waxen cells ; the two-winged flies, Volucella and Conops, and the larvse of what is either an Anthomyia or Tachina-like fiy ; several species of Anthrax, the Coleopterous Anobium paniceum of Europe, Meloe, Stylops, and Anthero- pliagus ochraceus are parasitic on Humble-bees.* The habits of the genus Apathus are not clearly known, but they are supposed to pi'cy, in the larva state, upon the larvae of Bombus, being found in their nests ; their habits, so far as known, ally them with Nomada. The species are distinguished by the tibiae being convex, instead of concave, as in Bombus, while the mandibles of the females are acute, triangular, biden- tate, being spatulate and three-toothed in Bombus, and they have no pollenigerous organs. There are males and females onty, as in all the remaining genera of the family. Apathtus Ashtonii (Plate 3, Fig. 1) is found in the Northei'n States. * Explanation of Plate 3. — Parasites of the Humble and Leaf-cutter Bees. Fig. 1, Apathwi Ashtonii. Fij;. 2, Nephoptcryx Edmandsii ; a, larva; b, pupa. Fig. 3, 3«, Micrognster nephoptericis, an Ichneumon jiarasite of Nephopteryx. Fig. 4, Antherophngus ochraceus. Fig. 5, Anthomyia'! larva; a, side view. Fig. (i, lle- cently hatched larva of Stylops Childrenii; a, side view. Fig. 7, larva; a, pnpa of Anthophorahia megachilis, a Chalcid parasite on ]Megacliilc. Fig. 8, Pteratomtis Putnamii, an exceedingly minute Proctotrupid Hy, supposed to be jiarasiticon An- thor|)horabia megachilis; a, a hind wing. Fig. 9, a Mite found in the nests of Humble-bees. 1 3 2 H YMENOrXEK A . X'jIocojKi, the Carpenter-boe, is "the hirgest and most l)ulky of all known bocs," but less hirsute than Bonibus, while tlie basal joint of the labial palpi is almost four times as long as the second ; and the maxillary palpi are six-jointed, the mouth- parts being \ery highly organized. The larva of X. Virtjlnica (Plate 4, Fig. 3, adult ; Fig. 4, larva; Fig. 5, nest) is slenderer tlian that of Bombus, the bod}' tapering more rapidly towards each end. The power of boring the most symmetrical tunnels in solid wood reaches its perfection in the large Virginian Carpenter- bee {Xylocopa Vir(ji)iifa). We have received from Mr. James Angus, of West Farms, N. Y., a piece of trellis for a grape- vine, made of jnne wood, containing the cells and young in various stages of growth, together with the larvse and chrysa- lids of Anthrax siunosa (Plate 4, Fig. G, larva; Fig. 7, pupa), a species of % parasitic on the larva of the bee, and which l)uries its head in its soft body and feeds on its juices. Mr. Angus thus writes us regarding its habits, under date of July ID : "I asked an intelligent and observing carpenter yes- terday, if he knew how long it toolc the Xylocopa to bore her tuiniel. He eaid he thought she bored about one-quarter of an inch a day. I don't tliink myself she bores n^ore than one- half inch, if she does that. If I mistake not, it takes her about two days to make her own length at the hrst start ; but this being across the grain of the wood may not be so easily done as the remainder, which runs parallel with it. 8he always follows the grain of the wood, with the exception of the en- trance, which is about her own length. The tunnels run from one to one ajid a half feet in length. Tliey generally run in opposite directions from the opening, and sometimes other gal- leries are run above the lirst, using tlie saine opening. I think they oidy make new tunnels when old ones are not to be found, and that the same tunnels are used for many years. Some of the old tuimels are very wide. I liave found parts of them about an inch in diameter. I think this is caused by rasping off the sides to procure the necessary material for con- structing their cells. The partitions are composed of wood- raspings, and some sticky fluid, i^robably saliva, to make it adhere. APIARI^.. 133 "The tunnels are sometimes taken possession of by other bees and wasps. I think when this is the case, the Xyloeopa prefers making a new cell to cleaning out the mud and rubbisli of the other species. I frequently find these bees remaining for a long time on the wing close to the opening, and bobbing their heads against the side, as if fanning air into the opening. I have seen them thus employed for twenty minutes. Whether one bee, or more, makes the tunnel, that is, whether they take turns in boring, I cannot say at present. In opening the cells, more than one are generally found, even at this season. About two weeks ago, I found as many as seven, I think, in one."* Tlie hole is divided by partitions into cells about seven-tenths of an inch long. These partitions are constructed of the dust or chippings made by the bee in eating out her cells, for our active little carpenter is provided with strong cutting jaAvs, moved by powerful muscles, and on her legs are stiff brushes of hair for cleaning out the tunnel as she descends into the heart of the solid wood. She must throw out the chips she bites off from the sides of the burrow with her hind legs, pass- ing the load of chips backwards out of the cell with her fore- limbs, which she uses as hands. The partitions are built most elaborately of a single flattened band of chips, which is rolled up into a coil four layers dee]*. One side, forming the bottom of the cell, is concave, lieing *" Since writing the above I have opened one of the new holes of Xylocopa whicli m;is commenced between three and fonr weeks ago, in a iiine slat used in the staj;ing of the greenhouse. The dimensions were as follows: Opening fully ;i-S wide ; depth 7-lG ; whole length of tunnel G and 5-l() inches. The tnunel brancliLM' both ways ftom the hole. One end, from opening, was 2 and 5-8, containing tluc«; cells, two with larva and pollen, the third empty. The other side of the opening, o'- the rest of the tunnel, was empty, with the exception of the old bee (only one) at work. I think this was the work of one bee, and, as near as I can judge, aboiic twenty-live days' work. Width of tunnel inside at widest !)-l(J inch. For bome days tliis bee has been discharging a great quantity of saw-dust and jjollen, which I had collected by )ilacing a vessel under it. It would seem that she had cells constructed also in the opposite side of the hole, and that she removed them to enlarge the tunnel. Among the stuff thrown out, I find a partition of a cell nearlj' entire. I have just found a Xylocopa bobbing at one of the holes, and in order to ascer- tain the depth of the tunnel, and to see whether there were any others in them, I sounded with a pliable rod, and found others in one side, at a depth of live and oih" half inches; the other side was four inches deep, without bees. The morning was cool, so that the object in bobbing could not be to introduce fresh currents of air, but mu>t have had some relation to those inside. The legs on such occasions are, as 1 have noticed, loaded with polleu.-'— American Naturalist, vol. 1, p. 370. 134 IIYMENOPTERA. beaten down and smoothed olT by the bee. The other side of the partition, forming the top of the cell, is flat and rough. At the time of opening the burrow, July 8th, the cells con- tained nearly full-grown larvie, with some half developed. Tliey were feeding on the masses of pollen, which were as large as a thick kidney-bean, and occupied nearly half the cell. Sa- pyga repanda is [)arasitic in the cells of Xylocopa violacea of Southern Europe. The habits and structure of the little Cerathici alh' it closely with Xylocopa, as it hollows out the stems of plants, and builds in them its cylindrical cells. This bee is oblong in form, with tridentate mandibles, and a short labrum. The maxillar^^ palpi are six-jointed, and the labial palpi are two-jointed. Ceratina duplaSay is a common small bright-green smooth-bodied species, which, in the middle of May, according to Dr. Harris' MS. notes, tunnels out the stems of the elder or blackberry, syringa, or any other pithy shrub, excavating them often to a depth of six or seven inches, and also, according to Mr. Haldeman (Harris MS.), bores in Cocorus. She makes the walls just wide enough to admit her body, and of a depth capable of holding three or four, often five or six cells (Plate 4, Fig. 11). The finely built cells, with their delicate silken walls, are cylindrical and nearly square at each end, though the free end of the last cell is rounded off. They are four and a half tenths of an inch long, and a little over one-third as broad. The bee places them at nearly equal distances apart, the slight interval between them being filled in with dirt. Dr. T. W. Harris* states that, "May 15, 1832, one female laid its eggs in the hollow of an aster-stalk. Three perfect in- sects were disclosed from it July 28th." The observations of Mr. Angus, who saw some bees making their cells. May 18th, also confirms this account. The historj^ of our little upholsterer is thus cleared up. Late in the spring she builds her cells, fills them with pollen, and lays one or more eggs upon each one. Thus in about two months the insect completes its transforma- tions ; within this period passing through the egg, the larval and chrysalid states, and then, as a bee, living through the win- ter. Its life thus spans one year. * According to a note iu MSS. deposited in the Library of the Boston Society of Natural History. APIARI^. 135 The larva (Plate 4, Fig. 10) is longer than that of Mega- chile, and eonipared with that of Xylocopa, the different seg- ments are much more convex, giving a serrate outline to tlie back of the worm. The pupa, or clnysalis, we have found in the cells the last of Jul}-. It is white, and three-tenths of an inch long. It differs from that of the Leaf-cutter bee in having four spines on the end of the bod}-, and in having a much longer tongue and maxilla:;, both being almost twice as long. In none of the wild bees are the cells constructed with more nicety than those of our little Ceratina. She bores out with her jaws a long deep well just the size of her body, and then stretches a thin delicate cloth of silk, drawn tight as a drum- head, across each end of her chambers, which she then fills with a mixture of pollen and hone}'. Her young are not, in this supposed retreat, entirely free from danger. The most invidious foes enter and attack them. Three species of Ichneumon-flies, two of which belong to the Chalcid family, lay their eggs within the body of the larva, and emerge from the dried larva and pupa skins of the bee, often in great numbers. The smallest parasite, belonging to the genus Anthophorabia (so called from being first known as a parasite on another bee, Anthophora), is a minute species found also abundantly in the tight cells of the Leaf-cutter bee. The species of Anthklium, according to Smith, are gaily marked with yellow bands and spots ; the ligula is almost twice as long as the labial palpi, and acutely pointed ; the paraglossfe are short, the maxillary palpi are two-jointed, and there are two subcostal cells. The males are longer than the females, with an elongated and stoutly toothed abdominal tip. The female lines her nest, situated in any hole convenient for its purpose, with down from woolly-stemmed plants. They pass the winter in the larva state, and the bees do not appear until mid-summer. The species mostly occur in the old world. In Anthophora, which approaches nearer to Bombus in its plump and hairy body than the two preceding genera, the lig- ula is twice as long as the labial maxilljE, ending in a bristle- like point ; the basal joint of the hind tarsus is thickly hirsute, while the middle tarsus of the males is generally elongated. The species are gregarious, their numerous cells, while indepen- 136 HYMENOPTERA. (lent, are crowded together in grassy banks. Species of Melecta are parasitic on tliem, ovipositing in their cells. The lar\ie are infected by the Chalcid Hies, Anthophorabia and Monodontomerus, and by a peculiar species of Mite, Hete- ropus ventricosus, described by Newport. Say has described Anthophora ahrupta and ^1. taurea from Indiana. In Eucera the antemut are very long, while the body is still plump and hairy : our more common form in the Middle States is Eucera macidata St. Fargeau. The species are likewise gregarious, and, according to Smith, their habits are precisely the same as those of Anthophora. In Megachile, the Leaf-cutter Bee, the head is broad, the body stout, oblong, the ligula is about one-half longer than the labial palpi, being quite stout, while the paraglossaj an; short and pointed ; the maxilhe are long and sabre-shaped, while their palpi are short and two-jointed. There are two subcostal cells in the fore wing. It is a thick-bodied bee, with a large square head, stout scissor-like jaws, and with a thick mass of dense hairs on the under side of the tail for the pur- pose of carrying pollen, since it is not provided with a pollen basket as in the Honey and Humble-bees. The larva is broadei- and flatter than that of Bombus, the raised pleural region is a little more prominent, and the raised, thickened tergal portion of each ring is more prominent than in Bombus. The Megachile lays its eggs in burrows in the stems of the elder (Plate 4, Fig. 9), which Ave have received from Mr. James Angus ; we have also found them in the hollows of the locust tree. Mr. F, W. Putnam thus speaks of the economy of Jf. centuncularis, our most common species. ''My attention was first called, on the 2Gth of June, to a female busily en- gaged in l)ringing pieces of leaf to her cells, which she was build- ing under a board, on the roof of the piazza, directly undei- lu}' window. Nearly the whole morning was occupied by the bee in bringing pieces of leaf from a rose-bush growing about ten yards from her cells, returning at intervals of a half minute to a minute with the i)ieces which she carried in such a manner as not to impede her walking Avhen she alighted near her hole. [We give a figure of the Leaf-cutter bee in the act of cutting out a circular piece of a rose-leaf (Plate 4, Fig. 8). She APiARi^:. 137 alights upon the leaf, and in a few seconds swiftly runs her scissors-like jaws around through the leaf, bearing off the piece in her hind legs.] About noon she had probal)ly com- pleted the cell, upon which she had been engaged, as, during the afternoon, she was occupied in bringing pollen, preparatory to laying her single egg in the cell. For about twenty days the bee continued at woik, building new cells and supplying them with pollen. . . . On the 28th of July, upon removing the board, it Avas found that the bee had made thirty cells, arranged in nine rows of unequal length, some being slightly' curved to adapt them to the space under the board. The longest row contained six cells, and was two and three-quarters inches in length ; the whole leaf-structure being equal to a length of fifteen inches. Upon making an estimate of the pieces of leaf in this structure, it w'as ascertained that there must have been at least a thousand pieces used. In addition to the labor of making the cells, this bee, unassisted in all her duties, had to collect the requisite amount of pollen (and honey?) for each cell, and la}' her eggs therein, when com- pleted. Upon carefully cutting out a portion of one of the cells, a full-grown larva was seen engaged in spinning a slight silken cocoon about the walls of its prison, which were quite hard and smooth on the inside, probably owing to the move- ments of the larva, and the consequent pressing of the sticky particles to the walls. In a short time the opening made was closed over by a veiy thin silken web. The cells, measured on the inside of the hard walls, were .35 of an inch in length, and .15 in diameter. The natural attitude of the larva is some- what curved in its cell, but if straightened, it just equals the inside length of the cell. On the 31st of July, two female bees came out, having cut their way through the sides of their tjells." In three other cells "several hundred minute Ichneu- mons [Anthophorabia megachilis] were seen, which came forth as soon as the cells were opened." (Com. Essex Inst., vol. iv. p. 105, 1864.) Meijacldle integer Say IMS., according to Dr. Harris (MS. notes), forms its nest of leaves the first of August. This spe- cies is twice as large, but closely resembles Megacliile hrevia of Say. The front of the head is covered with dense ochreous 138 HYMENOPTERA. hairs, becoming shorter and black on the vertex. The nest, preserved in the Harris collection, now in the Museum of the Boston Society of Natural History, is made of rose-leaves, and is scarcely distinguishable from that of M. centimcularis. Osmia^ the Mason Bee, is another genus of Carpenter or Upholsterer bees. The species are generally bluish, with greenish reflections, with smooth shiny bodies, and the species are of smaller size than in Megachile. The tongue in this genus is three times as long as the labium, tapering from the base to the acute apex, and clothed with short hair. Mr. F. Smith states that the larva of the English species hatch in eight days after the eggs are laid, feeds ten to tAvelve days, when it becomes full-grown, then spins a thin silken cjvering, and remains in an inactive state until the following spring, when it completes its transformations. The habits of the little Mason-bees are quite varied. They construct their cells in the stems of plants and in rotten posts and trees, or, like Andrena, they burrow in sunny banks. An European species selects snail-shells for its nest, Avherein it builds its earthen cells, while other species niditicate under stones. Curtis found two hundred and thirty cocoons of a British species (Osmia jxiretina) , placed on the under side of a flat stone, of which one-third were empty. Of the remainder, the most appeared between March and June, males appearing first ; thirty-five more bees were developed the following spring. Thus there were three successive broods for three succeeding years, so that these bees lived three years before arriving at maturity. Mr. G. R. AYaterhouse, in the Transactions of the Entomo- logical Society of London, for 1864 (3d series, vol. 2, p. 121), states that the cells of Osmia Jexicomelana "are formed of mud, and each cell is built separately. The female bee, having de- posited a small pellet of mud in a sheltered spot between some tufts of grass, immediately commences to excavate a small cavity, in its upper surface, scraping the mud away from the centre towards tlie margin by means of her jaws. A small shallow mud-cup is thus produced. It is rough and uneven on tlie outer surface, but beautifullj' smooth on the inner. On witnessing thus much of the work performed, I was struck with APIAEI^. 139 tlii'ee points. First, the rapidity with which the insect worked ; secondly, the tenacity with which she kept her original position whilst excavating ; and thirdly, her constantly going over work which had apparently been completed. . . . The lid is excavated and rendered concave on its outer or upper surface, and is convex and rough on its inner surface ; and, in fact, is a simple repetition of the first-formed portion of the cell, a part of a hollow sphere." The largest species of Osniia known to us is a very dark-blue species which seems to be undescribed. We will call it the wood-boring Osmia {Osmia lignivora). It is larger than the Osmia lignaria of Say, being just half an inch long. The head is much shorter, and less square than in Say's spe- cies. The front of the head below the antennae is clothed with dark hairs, but above and on the thorax with yellowish ochreous hairs. The body is deep blackish blue, with greenish reflec- tions. We are indebted to a lady for specimens of the bees with their cells, which had been excavated in the interior of a maple tree several inches from the bark. The bee had industri- ously tunnelled out this elaborate burrow (Plate 4, Fig. 12), and, in this respect, resembles the habits of the Carpenter-bee (Xylocopa) more closely than any other species of its genus. The tunnel was over three inches long, and about three- tenths of an inch wide. It contracted a little in width between the cell, showing that the bee worked intelligently, and wasted no more of her energies than was absolutely necessary. The burrow contained five cells, each half an inch long, being rather short and broad, Avith, the hinder end rounded, while the opposite end, next to the one adjoining, is cut oft' squarely. The cell is somewhat jug-shaped, owing to a slight constriction just behind the mouth. The material of which the cell is com- posed is stout, silken, parchment-like, and very smooth within. The interstices between the cells are filled with rather coarse chippings made by the bee. The bee cut its Avay out of the cells in March, and lived for a month afterwards on a diet of honey and water. It eagerly lapped up the drops of water supplied by its keeper, to whom it soon grew accustomed, and whom it seemed to recognize. The female of Osmia lignaria Say MS., according to Dr. 140 HYMENOPTERA. Harris' MS. notes, was found in tlie perfect state in cocoons within earthen cells under stones, April loth, Tlie cell she con- structs is half an inch long, oval, cylindrical, and contracted slightly into a sort of neck just before the opening for the exit of the bee. From Mr. James Angus I have received the pellets of pollen, about the size of a pea, in which it deposits its eggs ; the larvae were about one-third grown in August. Tliis species is larger than CMmia simiUima of Smith, while the male antennae are mucli paler, being fuscous. The front of the head is covered with long dense yellow ochreous hairs. The vertex is not of so dark a green as in 0. shniUima, and is covered Avith coarse punctures. The thorax is heavily clothed with yellow ochreous, tliick hairs. The abdomen is yellowish, and nnich more hairy. The legs are stout, fuscous, with yel- lowisli hairs. Length. .35 inch. Our smallest and most abundant species is the little green (Mil la siiiu'Uima of Smith. It builds its little oval, somewhat urn-shaped cells, against the roof of the large deserted galls of the oak-gall fly (Diplolepis confluentus), placing them, in this instance, eleven in number, in two irregular rows, from which the mature bees issue through a hole in the gall (Plate 4,* Fig. 14. From specimens comnninicated by Mr. F. G. Sanborn), Tlie earthen cells, containing the tough dense cocoons, were arranged irregularly so as to tit the concave vault of the larger gall, which was about two inches in diameter. On emerging from the cell the Osmia cuts out with its powerful jaws an ovate lid, nearly as large as one side of the cell. Both sexes may be found in April and May in the flowers of the willow ♦Exi'LAXATioN OF PLATE 4. — Fig. 1, a cell of the Humble-bee; natural size, with the ])ollou mass uiion the toj). Fig. 2, end view of the same mass, showing tlic three eggs laid in three divisions of the cavity. Fig. 3, Xylocopa Virginica. the Carpenter IJee. Fig. 4, tlie larva of Xylocopa Virt)i)iica; natural size. F'ig. 5, tlie nest containing flie cells of the same, with the partitions and pollen masses, oil whii'h the young larva is seen in the act of feeding; natural size. Fig. (J, young larva oi Anthrax sinuosn; side view. Fig. 7, pupa oi Anthrax sinuosa, side view; natural size. Fig. 8, the Leaf-cutter Bee (.Aferfarhilc), on a rose leaf, in the act of cutting out a circular piece. Fig. 9, cells of Megachile, in the elder; natural size. Fig. 10, larva of Ccmthm ditpla, the little green Upholsterer Ree: enlarged. Fig. 11, cells of the same in the stem of the elder; natural size. Fig, 12, cells of O.swmVj Kf/nivora, new species, the wood-devouring iMason-bce, exca- vated in the maple; natural size. Fig. ]:{, cells of (h/nia simU/imn, the common grei'u Masonbee, built in the deserted gall of the Oak-gall Fly. Fig. 14, a .single earthen cell of the same; natural size. Fig. 15, pollen mass, or bee-bread of Osviia llf/naria; natural size. It is made up of distinct pellets of pollen, which are probably stuck together with saliva. I Plate 4. ARCHITECTURE OF BEES. APIARI^. 141 and fruit trees which blossom later. The antenna? arc bhick, and the green body is covered witli fine white hairs, becoming yellowish above. In the Harris collection are the cells and specimens of Osviia jxicijica Say, the peaceful Osmia, which, according to the man- uscript notes of Dr. Harris, is found in the perfect state in earthen cells (Plate 5, Fig. 2) beneath stones. The cell is oval cylindrical, a little contracted as usual with those of all the spe- cies of the genus, thus forming an urn-shaped cell. It is half an inch long, and nearl}^ three-tenths of an inch wide, while the cocoon', which is rather thin, is three-tenths of an inch long. The following genera, called Cuckoo Bees, are parasitic on other bees, laying their eggs in the cells, or nests, of their host. In Ccelioxys the body is stout, and the bee closely mimics its host, Megachile. The ligula is very long, being almost three times the length of the labium, and the paraglossse are wholly wanting ; the maxillary palpi are short, three-jointed, and the abdominal tip of the male is variously toothed. Qjelioxys octo- dentata Say, is abundant late in the summer about flowers. An allied genus, 3felecta, is parasitic on Anthophora, and Epeolus is parasitic on Colletes. The species of Nomada are ver}' numerous ; in all, the tongue is long and acute, with paraglossa; about one-fourtli as long as the tongue ; the maxillary pair of palpi are six-jointed ; and there are three subcostal cells. The species in their slen- der, smooth, gaily colored body resemble the wasps. These Cuckoo-bees lay their eggs in the nests of Andrena and Ila- lictus, and, according to English authors, Panurgus and Eucera. where they may be found in all stages of development corre- sponding to those of their hosts. The females do not sting severely. The species emit sweet, balmy, or balsamical odors. Shuckard states that these bees should be killed Avith burning- sulphur to preserve their bright colors. The larvae differ greatl}' from those of their hosts, Andrena, the head being much smaller, the body being smoother and rounder, and belonging to a more degraded, lower type. The whole bod}' is more attenuated towards both extiemities. The pupa differs from those of any other genus of this family known to us, except Andrena, by having three conspicuous 142 HYMENOPTERA. spines on the upper and posterior edge of the orbit, which arc also found in the pupa of Stigmus, a Crabronid genus, and which evidently aid in locomotion. Thus the same law of degrada- tion obtains in these highly organized bee-parasites as in the lower parasitic species, though in a much less marked degree. From specimens found in the nests of Andrena and Halictus, collected at Salem by Mr. J. H. Emerton, and now in the Mu- seum of the Essex Institute, we have been enabled in great part to clear up the history of this bee. We have found in the nests of Andrena vicina both sexes of Nomada imbricata Smith, and several females of Nomada palcheUa of Smith ; and in the cells of Halictus parallelus Say, specimens of Nomada imbri- cata. Both full-grown larvae and pupae of different ages, up to the adult Nomada, ready to take leave of its host, were found in the cells of the Andrena vicina. It seems, there- fore, that the newly hatched young of Nomada must feed on the pollen mass destined for the Andrena. But there seems to be enough for both genera to feed upon, as the young of both host and parasite were found living harmoniously to- gether, and the hosts and their parasites are disclosed both at the same time. Does not this mild sort of parasitism in No- mada throw much light on the probable habits of Apathus, the Humble-bee parasite? It is more than probable that the Apa- thus larvae simply eat the food of the Bombus larvae, and do not attack the larvae of their hosts. Both Nomada and Apathus in their adult stages live harmoniously with their hosts, and are seen gathering food from the same flowers, and flying about the same nest. In the second subfamily, Andrenetce , the ligula, or tongue, is for the most part short and broad, and the maxillary palpi have four joints of equal size. In Sphecodes the body is smooth and wasp-like, and in its habit of running and flying in dry sandy places, it resembles Sphex, whence its generic name. The abdomen is generally light red, farther aiding in the resemblance to the Spliegidw . The ligula is short, lancet-shaped, fringed with setse ; the para- glossae are not so long as the tongue, while the labial palpi are shorter than the paraglossae, and the maxillae are broad, lan- ceolate, with six-jointed palpi. The antennae of the males are APIARI.E. 143 short and sometimes moniliform. Sphecodes dichroa Harris is our most common species. Mr. F. Smitli, from direct observa- tion, states that this genus builds cells, though earlier authors have stated that it is parasitic on Ilalictus and Andrena. Prosopis is generally yellow on the face, and is "less pubes- cent than any of the bees." The tongue is broad, subemar- ginate, the paragiosste reach a little beyond the tongue ; the labial palpi are as long as the tongue, while there are two sub- costal cells in the fore wings. Smith states that the genus is not parasitical as formerly supposed, as he has "repeatedly bred them " from cells laid in a regular order in the hollow of bramble stems. Mr. S. Saunders has also raised them in Alba- nia where "they construct their cells in bramble sticks (which they bore in the same manner as Colletes) with a thin transpa- rent membrane, calculated for holding semi-liquid honey, which they store up for their young. The species are much attacked by Stylops." Like Sphecodes and Ceratina, this genus, accord- ing to Smith, is unprovided with poUenigerous organs. We have several species in this country of which P. affinis Smith, and P. eUiptica Kirby, are found northward. The habits of our species are not known. AugocJdora comprises beautiful shining metallic green spe- cies, very commonly met with. The thorax is globose, and the anterior wings have one marginal and three submarginal cells ; the first submarginal cell as long as the second and third united. AugocJdora purus Smith is a small, green, rather common species. Mr. J. H. Emerton has found its nests in Sa- lem, near those of Andrena. The mouth of the hole opened under a stone, and was built up so as to form a tube of sand (Plate 5, Fig. 1). The burrow on the 28th of June was four inches deep. Andrena is a genus of great extent, and the species are often difficult to distinguish. The lanceolate tongue is moderately long, and the paraglossse are half as long as the tongue itself, while the six-jointed maxillary palpi are longer than the maxillae themselves. The wings have three subcostal cells, with the rudiments of a fourth one ; the second is squarish, and the third receives a recurrent nervure near the middle. The pos- terior legs " have a long curled lock upon the trochanter be- 144 HYMEXOPTERA. neath, and the anterior upper surface of the femora is clothed with long loose hair, which equally surrounds the whole of the tibijB." (Shuckard.) The abdomen is banded more or less conspicuously with reddish. The larva (Fig. 80) is stout and thick, with a head of moder- ate size, and the mouth-parts are a little shorter than usual, the maxilla} and labium especially. The segments of the bod}^ are much more convex (angularly so) than usual, giving a tuberculate outline to the body. It is stouter than that of Halictus, the wings' are less convex than in that genus ; while the maxilhe are much stouter and blunter. The pupa is distinguished from the other genera by much the same characters as the imago, excej^t that there are two tubercles on the vertex near the ocelli. From a comparison of all its stages, this genus stands inter- mediate between those placed above, and Halictus, which, in all its characters, is a more degraded form. The males often differ widely from the other sex, in their broad heads and widely spreading bidentate mandibles. Mr. Emerton has observed the habits of our most common species, Andrena vicina Smith, which builds its nest in grassy fields. The burrow is sunken perpendicularly, with short pas- sages leading to the cells, Avhich are slightly inclined downwards and outwards from the main gallery. The walls of the gallery are rough, but the cells are lined with a mucus-like secretion, which, on hardening, looks like the glazing of earthen-ware. In Fig. 80 Mr. Emerton gives us a profile view of natvu'al size, of the nest showing the main liurrow and the cells leading from it ; the oldest cell, containing the pupa (a) is situated nearest the surface, while those containing larvsc (&) lie between the pupa and the cell (e) containing the pollen mass and egg resting upon it. The most recent cell (/) is the deepest down, and contains a freshly deposited pollen mass. At c is the begin- ning of a cell ; g is the level of the ground. The bees were seen at work on the 4th of jNIay, at Salem, Mass., digging their holes, one of which was alread}^ six inches deep ; and by the 15th, hundreds of holes were observed. On the 28th of May, in unearthing six holes, eight cells were found to contain pol- APIARI.*:. 14. 'm<0 6^N ^ X^ '"^ifij i'^:^/ leu, and two of them a small larva. On the 29111 of June si\ full-grown larvffi were exhumed, and one about half-grown. About the first of August the hirva transforms to a pupa, and during the last week of this month the mature bees appear. In Ilalictus, which is a geiuis of great extent, the head is trans- verse, and flatfish ; the mouth- parts are of moderate length, the tongue being very acute, with acute paraglosste half the length of the tongue, while the labial palpi are not quite so long as the paraglossiB. There are three subcostal cells in the wings, with the rudiments of a fourth often present, and the second cell is squarish. The abdomen is ob- long ovate, with a longitudinal linear furrow on the tip in the female. In the males the body is longer and the antennie more filiform and slender than usual in this family. The larvte are longer, and with more acutely convex segments than in Andrena. The pupa3 differ much as the adult l)ees from Andrena, especially in the shorter mouth-parts. Halidus 2')ciraUeh(s Say excavates cells almost exactly like those of Andrena; but since the bee is smaller, the holes are smaller, though as deep. JMr. Emerton found one nest, in ;i path, a foot in depth. Another nest, discovered September *Jth. was about six inches deep. The cells are in form like those of Andrena, and like them are glazed within. The egg is rather slender and much curved; in form it is long, cyliiidrical, ob- tuse at one end, and much smaller at the other. The ihr\a 10 \ «^ '#^ Fia: 80. V> 146 Hy:\rENOI'TEKA. Fisr. 81. (Figs. 79, 81) is longer and slenderer, and quite different from the ratlier broad and flattened larva of Andrena. The body is rather thick behind, but in front tapers slowl}^ toAvards the head, wliich is of moderate size. Its bod}^ is somewhat tuberculated, the tubercles aid- ing the grub in moving about its cell. Its length is .40 of an inch. On the pupa are four quite dis- tinct conical tubercles forming a transverse line just in front of the ocelli ; and there are also two larger, longer tubercles, on the outer side of each of which an ocellus is situated. Figure 82 represents the pupa seen from beneath. Search was made for the nests on July 16th, when the ground was very hard for six inches in depth, below which the soil was soft and fine, and over twenty cells w^ere dug out. "The upper cells contained nearly mature pupre, and the lower ones larvae of various sizes, the smallest being hardly distinguishable by the naked eye. Each of these small larvae was in a cell by itself, and situated upon a lump of pollen, which w^as of the size and shape of a pea, and was found to lessen in size as the larva grew lai'ger. These young were probably the offspring of several females, as four mature bees were found in the hole." (Emerton.) The larva of an English species hatches in ten daj's after the eggs are laid. Another brood of bees appeared the middle of September, as on the ninth of that month (18G4) Mr. Emerton found sca'- eral holes of the same species of bee made in a hard gravel road near the turnpike. When opened, they were found to contain several bees with their young. September 2, 1867, the same kind of bee was found in holes, and just ready to leave the cell. Like Bombus, the females are supposed to hybernate, the males not appearing until late in the season. Like Andrena. these bees suffer from the attacks of Stylops, and according to Shuckard, an Ichneumon preys upon them, while certain spe- cies of Cerceris, Philanthiis, and Crabro carry them off to store their nests with. VESPARI^. 147 In CoUetes the females, as Shuckard observes, resemble tho workers of the Honey-bee, while there is eonsiderable disparity between the sexes, the males being much smaller, the tongue and maxilljB very short ; and the four-jointed labial paliii much shorter than the paraglossae. There are three subcostal cells, with the rudiments of a fourth. These bees form large colo- nies, burrowing in the eai'th eight or ten inches deep, lining thei'/ cells "at the farther end with a very thin transparent mem- branaceous coating, resembling goldbeaters' skin." The}' thus furnish six or eight cartridge-like cells, covering each with a cap, "like the parchment on a drum-head." Smith, from whom we have been quoting, states that 3Iiltogramma punctata^ which is a Tachina-like fly, and the Cuckoo-bee, Epeolus variegatus, have, in Europe, been reared from their cocoons. Vespari^ Latreille, Wasps. In this family, which comprises about 900 species, the body is more attenuated, more cylindri- cal, with a harder and smoother tegument than in the Ap i a r i ct^ . In the species with densely populated colonies, such as Vespa and Polistes, there are workers Avhich are often verj^ numerous, while in Eumenes and Odynerus, etc., there are only males and females. The antennae are elbowed, the mandibles are large, stout ; the maxillas and labium of var3nng length ; the maxil- lary palpi are six-jointed ; while on the labial palpi, which are four-jointed, there are well-developed paraglossae. The pro- thorax is prolonged on each side to the insertion of the wings which are long and narrow, and once folded longitudinall}' when at rest ; the fore pair have two or three subcostal cells ; the hind shanks and tibiae are smooth. The eggs, when first laid, are globular, soon becoming oval. The larvae of this family are soft, fleshy, with larger heads in proportion to the rest of the body, than in the Apiarice; the antennal tubercle, or rudimentary antennae, are more dis- tinct, and the mandibles are larger. The surface of the body is smoother in Vespa and Polistes, but more tuberculated in th(! solitary genera, Odynerus and allies, while the end of the body is more acute. As in the Apiarice the higher genera are social, building papery nests, while the lower are solitary and build cells of mud or sand in protected places. i48 IIYMENOPTERA. In Vespa, the Paper Wasp, the liguLa is squarish, with the paraglossae nearly as k)ng as the tongue, the outer maxillary lobes rounded oval, half as long as the palpi, and the labial maxillae are scarcely longer than the tongue. The abdomen is broad at base, acutely conical. The nests are either with or without a papery covering, supported by a short pedicel. Such females as have h3'bernated, begin to make their cells in the earl}'^ part of summer. Smith states that the soli- tary female wasp "begins b}' making three saucer-shaped re- ceptacles, in each of which she deposits an egg ; she then proceeds to form other similar -shaped receptacles, until the eggs first deposited are hatched and the young grubs require a share of her attention. From the circular bases she now be- gins to raise her hexagonal cells, not building them up at once, but from time to time raising them as the j'oung grubs grow. (Froc. Ent. Soc, London, 1858, p. 35.) Waterhouse states that the cells formed by the solitary fe- male early in the season appear *•' to be built entirely of glisten- ing, whitish, silk-like threads which I have little doul)t are a secretion from tlie insect, all the threads being lirmly attached together as if they h;ul originally been of a glutinous nature." The cells formed later in the season by the workers, differ hi consisting of masticated rotten wood. "Almost simultane- ously with the commencement of the cells, it appears that the nest-covering is commenced. At first it has the appearance of a miniature umbrella, serving to shelter the rudimentary cells." Plate 5, Fig. 3, shows a group- of cells suri'ounded by one layer of paper, and the beginning of another. As the nest grows larger the cells are ar- ranged in galleries, supported by pedicels, and the number of layers in the outside covering greatly increases in number. While our common and largest species, Fesjr^tt macidata Linn. (Fig. 83), and the yellow Avasp, FJs-8:5. Y, areuaWaFabr., build papery nests consisting of several galleries, with the mouth of the cells directed downwards, the East Indian species, V. orientalis, VESPARIiE. 149 builds its cells of cla}-, and, according to Waterhouse, "tlic work is exceedingly beautiful and true." Another species, according to Smith, makes its nest of sandy loam, the exterior being so hard that a saw used in opening one of its sides was blunted. The larva of Vespa arenaria is long and cylindrical, not so much curved as in Polistes. Its position in its cell corre- sponds to its form, as the cell is longer and narrower than that, of Polistes. Each segment of the body is posteriori}^ some- what thickened, as is the lateral (pleural) ridge of the body. The tip of the abdomen is rather blunt, the last sternite be- ing large and transverse. The pupa is provided with a single tubercle on the vertex, where there are two in the Crabro ii- idce and Sphegidm. By the time the nest of V. arenaria is large enough to contain ten full-grown larvoe, and has about fourteen cells in all, being about an inch in diameter, the occupants of the two or three central cells will have changed to pupae, and one wasp will have been excluded. In a nest of the same species two inches in diameter, there were a second brood of larviie. The outer row of cells were occupied by pupjie. while the central ones, emptied of the first bi'ood, were filled with a second brood of larva?. Evidently as soon as an imago leaves its cell, the female deposits an egg therein, as very minute larviB were found occup^'ing cells next to those containing large full-grown larvae In comparing a number of \)\\\)-cC from a large nest, they will be found to be in all stages of perfection, from the larva which has ceased feeding, and is preparing to transform, to the imago, still veiled by its thin subimago pellicle. It is dif- ficult to draw lines between these stages. Also when com- pared closely side b}* side, it is difficult, if not impossible to fine? any two pupiE just alike, the development proceeding very un- equally. Thus the limbs ma}- be more perfect than the antennae or certain parts may be less perfect in some tlian in others, while the limbs may be more highly colored like the imago. Like the bees, Vespa suffers from numerous parasites, includ- ing IJhipiphorous paradoxus, which is a beetle allied to Stylops. and Lebia (Dromius) linearis. The larva of Volucella is said J 50 HYMENOPTERA . to feed on the Vespa-larvse, and Mr. Stone says that Anthomyia incana is also parasitic in Wasps' nests, while two species of Ichnenmons, one of which is Anomalon vesparum, also in- fest the larvie. No parasites have been as yet detected in this country. The Hornet, V. crabro Linn., has, according to Mr. Angus, become domesticated about New York. This and the smaller wasps are sometimes injurious b}' eating into ripe fruit, but the injury is more than counterblanced by the number of flies and other insects they feed their young with. Indeed, as Saussure states, the species of Vespa are more omnivorous in theu* tastes than any other wasps. They live by rapine and pillage, and have obtained a worse repute than other insects more injurious. In spring and early summer they feed on the sweets of flowers ; but later in the season attack strawber- ries, plums, grapes, and other fruits, and often enter houses and there help themselves to the dishes on the table. The^' will eat raw meat, and then aid the butcher by devouring the flies that lay their eggs on his meats. They will sometimes destroy Honey- bees, attacking them on their return from the fields laden Avith pollen ; they throw themselves upon their luckless victims, and tear the abdomen from the rest of the body, and suck theii' blood, devouring only the abdomen. They fall upon flies and butterflies, and, biting off" their wings, feet, and head, devour the trunk. In attacking insects they use only their powerful jaws, and not the sting, diftering in this respect from the fossorial wasps. Saussure states that though wasps do not generally lay up food, yet at certain periods the}' do fill the cells with honey. The females feed their young with food chewed up and re- duced to a pulp. Saussure questions whether the larvae of one sex are not fed on animal and the other on vegetable food, since Huber had shown "what a great influence the kind of tbod exerts on the sex of Bees." But it is now known that the sexes of some, and probabl}' all insects are determined before the larviB is hatched. I have seen the rudiments of the ovi- positor in the half-grown larvjc of the Humble-bee, and it is most probable that those rudiments began to develop during »!mbryonic life. It is far more probable that the sexual diflfer- eiK^es are determined at the time of conception. VESPARIiE. 151 Westwood states that the larvne, which live hend-dowuward from the reversed position of tlie comb, retain tlieir position in the cell, while young, b}^ a glutinous secretion, and afterwards "•by the swollen front of the body which fills the open part of the cell." "Tlie female cells are mostly placed apai't from those of the males and neuters, those of the males being often mixed, but in a small number, in the neuter combs. The egg state lasts eight days, the larva state thirteen or fourteen, and that of the pupa about ten. After the imago has been produced, one of the old workers cleans out the cell, and fits it for the reception of a fresh inhabitant. The upper tier of cells, being first built, serves for the habitation of the workers ; the females, being produced at the end of the summer, occupy the lowest tiers." When about to transform the larvae spin a thin cover- ing, thus closing over the cell. In Polistes the paraglossai are slender, and a little longer than the long, or as in one instance noticed bj' us in P. Cana- densis, barrel-shaped ligula, which is split at the end ; the palpi are stouter, while the whole body is much longer than in Vespa ; the abdomen is subpedunculate, and the thorax is rather ob- long than spherical, as in Vespa. The larva dilfers from that of Vespa in its much larger head, and shorter, more ovoid form of the body, which is dilated in front so as to retain the insect in its cell, while the tip is more acute ; the antennal tubercles are closer together ; the clypeus is more regularly triangular and more distinct, while the labrum is much larger and excessive^ swollen, as are the mouth-parts generally. The mandibles are bidentate, where in Vespa they are tridentate. The pupa differs from that of Vespa, besides the usual generic characters, in having the tubercle on the head smaller. The nests of Polistes (Plate 5, Fig. 4, nest of P. annularis Fabr., from Saussure) are not covered in by a papery wall as in Vespa, but may be found attached to bushes, with the mouth of the cells pointed downwards. While at Burksville Junction, Va., in the last week of April, I had an opportunity of watch- ing three species beginning their cells on the same clump of bushes. They all worked in the same method, and the cells only difiered slightly in size. The cells were formed mostly of 1 2 HYMENOPTEKA . crude silk, and the threads could be seen crossing each other, the same structure being obser^•ed at the top and bottom of each cell. In the three-celled nest of Polistcs (Plate 5, Fig. 5, 5a) (irst noticed April 29th, there were but two eggs deposited, the tliird cell being without an egg, and a little smaller, and the rim not so high as in the other two. The outer edge did not seiiui to be perfectly circular, though stated by Water- house to be so in the incipient cells, for in some cases we de- tected two slight angles, thus making three sides, which, however, would be easily overlooked on casual observation ; as there are onl}^ two sides within, the cell, from being at its earliest inception hemispherical, or '"saucer-shaped," becomes live, and subsequently six-sided, and thus from being cir- cular, it is converted by the wasps into a hexagonal cell. In some cells, perhaps a majority, both in this and the other spe- cies, the newly made rim of the small cells is thinner than the parts below, and slightly bent inwards ; thus being quite the re- verse of the thickened rim of the cells of the Hive Bee. It would seem that the wasp plasters on more silk, especially on the angles, building them out, and making them more promi- nent, in order to complete, when other cells are added, their hexagonal form. The three cells are of much the same size and height when the third egg is laid, as we observed in another nest, that of PoUstes Canadensis (Linn.), built at the Defences of Washington, near Munson's Hill, June 9th. Again, when one or two more cells have been added to tlu» nest, anil there are four or five in all (Plate 5, Fig. 6 ; Ga, top view, in which there are four cells), two of them are nearly' twice as large as the others, while the fifth has been just begun. and is eggless. The form of the two which run np much higher than the others is the same as that of the smaller and shorter ones, i.e. they are on one side nearly semicircular, and on the other, partly hexagonal, and the angular sides show a tendency to be even more circular than when the others are built arouml them, for the little architect seems to bring out the angles more prominently when can-ying up the walls of the other cells. Thus she builds, as if by design, one and the same cell both by the "circular" and "hexagonal" methods, afterwards adopt- VESPARI.^. 153 iug only tlie latter, and if she devotes her attentions specially to plastering the corners alone, with the design of making tiie cell six-sided, then we must allow, contrary to Mr. Water- house's views, that the wasp builds the hexagon by choice, and not as the mere result of her blindly "working in segments of circles ;" for if our point be proved, and the most careful obser- vation of the wasp while at work is needed to prove it, then it may be shown that the wasp is a free agent, and can abandon one method of working at a certain stage of her work, anil adopt a different jnode of operating. The eggs are oval, pointed at the end, and glued to the in- side of the cell. They are situated midwa}'^ from the top and bottom of the incipient cell, and placed on the innermost sides, so that in a group of several cells the eggs are close together, only separated by the thin cellular walls. In a completed cell the egg is placed very near the bottom. For several days a Polistes Canadensis was engaged in build- ing its nest in my tent in camp near Washington. AVhen first noticed on June 9th, there were three cells, two of which con- tained eggs; and it was not for two days, the 11th, that the third cell was completed, and a third egg deposited in it. The wasp paid especial attention to strengthening the pedicel, going over it repeatedly for an hour or two with its tongue, as if lay- ing on more silken matter, and then proAed the work by its swiftly vibrating antenna. It would often fly out of the tent, and on its return anxiousl}'' examine each cell, thrusting its head deep down into each one. It gradually' became accustomed to my presence, but eventually abandoned the nest, without adding more cells. The others, while at work on the bushes, abscond- ed at my approach, and seemed very war}^ and distrustful, as if d 'sirous of concealing their abodes. Mr. Smith has. found Trig raolys hipustnlatus to be a parasite on Polistes lanio Fabr. (P. Canadensis Linn.), from St. Salvador, S. A. Saussure arranges the higher Vespidte into two parallel series. Vespa is offset b}^ Chartergus and Nectarina ; lower down we lind Tatua and Synoeca, while Polistes is offset by Polybia. These five genera are tropical, and in their habits, the genoi-al appearance of their nests, and in the number of individuals represent Vespa and Polistes of the temperate zone. The 154 HYMENOPTERA. genus Nectarina is a short plump wasp, somewhat like Odyne- rus in shape ; its distinguishing mark is the concealment of the postscutellum by the scutellum. Nectarina mellijica Say. of Mexico, builds a large nest externally like that of a wasp, but it is more irregular, and the papery covering consists of but one layer. The interior of the nest is very different, the galleries of cells, instead of being parallel, being arranged in concentric spheres, Chartergus has the tip of the cljpeus slighted excavated, and an oval sessile abdomen. C. chartarius Olivier makes an ex- ceedingly thick tough nest, attached by a broad base to the bough of a tree, about twice as long as thick, and ending in a cone, pierced in the centre by the entrance which passes through the middle to the basal gallery ; the other galleries are formed by a cuutinuation of the sides of the nest, and arranged in a conical plane. In Tatua, the abdomen is pedicelled, but the petiole is not enlarged, and the abdomen itself is very regularly conical. T. morio Cuvier, from Cayenne, forms a nest like that of Charter- gus ; but the galleries form a flat floor, and each gallery has an entrance from the outside of the nest, where in the latter there is one common entrance. Plate 5, Fig. 9, shows how the bases of the cells are laid out on the edge of a gallery. In Synaca the peculiarly shaped abdomen is cordate and compressed. The curious nest of S. cyanea Fabr. is formed of a single layer of cells fixed against the trunk of a tree, and covered in with a dense covering made from the bark of dead trees. Some nests of Synceca are three feet long. In the very extensive genus Polyhia, which resembles Polistes in its general shape, the abdo- men is pedicelled, and the mandibles ai'e four-toothed. The nests are somewhat like those of Chartergus, but much smaller. Sev- eral species occur in Mexico, and in Brazil the number of species is very great. In Apoica the abdomen is very long, and the third segment is as long as the second. Plate 5, Fig. 11, represents the nest of Ajyoica pallida Olivier, from Cayenne. It is improtected, with a conical base, and with a single row of cells. In Icaria we have an approach to Polistes in the slender series of cells composing the nest, forming two or three rows VESPART^. 155 only. Plate 5, Fig. 7, represents the nest of 7. guttatipennis Saussure, from Senegal ; 8, ground plan of a similar nest. These wasps are mostly distinguished from FolyLia by the petiole ending in a globular mass. Plate 5, Fig. 10, represents the elegant nest of MiscJiocyttarus labiatus Fabr., from Cay- enne and Brazil, which consists of a few cells supported by a long pedicel. The wasp itself much resembles Polistes, but the petiole is very much longer. The remaining genera noticed here arc solitary, building separate cells, and Avith only males and females. There are three subcostal cells in the fore wings, and the maxillte and labium are much elongated. In Eumenes the abdomen has a long pedicel, being sessile in Odynerus. While authors place Eumenes higher than Od}^- nerus, we would consider the latter as a higher, more cepha- lized form, since the abdomen is less elongated, and the head is larger. In Odynerus the ligula is long, deeply forked at the slender extremity, while the slender paraglossaj are shorter, ending in a two-toothed claw-like tip ; the maxillae are slender, and the palpi haA'e an elongated basal joint ; the clypeus is nearly' circular, toothed on the front edge. The larva differs from those of the higher Vesparim , in its more elongated head, the square clypeus, the unusually deep fissure of the bilobate la- brum, and in the larger tubercles of the bod}"-, as the larva is more active, turning and twisting in its cell, while feeding on its living food ; and in this respect it is more closely allied to the young Crahronidm . In the pupa of 0. alhoplmJenitns, the tip is more incurved than in the pupa of Vespa, so that the hind legs (tarsi) reach to the tip, and the abdomen is rounded ovate, while in Vespa it is oblong. The cells (Plate 4, Figs. 13, 14) of Odynerus albopJialeratus Sauss. have been detected like those of Osmia in a deserted g"all of Diplolepis confluens, where several were found in a row, arranged around one side of the gall, side by side, with tlie holes pointing towards tlie centre of the gall. The cells are half an inch long, and one-half as wide, being formed of small pellets of mud, giving a corrugated, granulated appearance to the outside, while the inside is lined with silk. 1 r>6 HYMENOPTERA. We have received from Mr, Angus deserted cells of Cera- tiua in a syringa stem, in which we detected a pupa of an Odynerus, perliaps 0. leucomelas ; tlie cell was a little shortei- thaji that of the Ceratina it had occupied. The cocoon of tlie Odynerus was of silk, and almost undistinguishable from the old cocoon of Ceratina. The wasp had disixjnsed with the necessity of making a mud cell. If future research shows that either this or any other species makes a nuid cell or not at will, it shows the intelligence of these little ''free-agents;" and that a blind adherence to lixed mechanical laws does not (obtain in these insects. The lar\ie of Odynerus and P^umenes are carnivorous. 1 found several cells of 0. albophaleyatus, June 22d, in the deserted nest of a Glisiocampa^ which were stored with inicro- lepidopterous larviii and pupye, still alive, having been para- 13-zed by the sting of the wasp. The larvue of the wasp was short and thick, being, when contracted, not more than twice as long as broad ; the rings of the bod\- are moderately convex, and the pleural region is faintly marked. Prof. A. E. Verrill has discovered the cells of an Och'uerus at New Haven, forming a sandy mass (Plate 5, Fig. 12) attached to the stem of a plant. In Enmones the lingua is very long, being narrower and more deeply divided than in Odynerus : tlie second subcostal space of the wings is long and narrow, while in Odynerus it i;> triangular. The genus is easily recognized l\y the very long- pedicel of the abdomen. Eumenes fratenni Saj' constructs 11 thin cell (Plate o,* Fig. 15) of pellets of mud, and as large * Explanation of Plate 5. Fig. 1. Month of the tunnel of Avgochlora pnrits . Trom Emertnn. Fig. 2. Cells of Osmia pacifica ; coaiinuuic.ated by Mr. Sanborn. Fig. 3. Vertical section of nest of Vespa with a grou)) of primitive cells surrounded by one layer of paper, and part of another; from Saiissure. Fig. 4. Nest of Po- li.-iles aiinuUtri.it; from Saussure. Fig. 5. Three primitive cells of Polistes; 5rt, top view of the -s.-ime, one being eggless. The sides adjoining are angular. Figs. G and *'im pedicellatum Pack., from stems of the Rose, Corcorus, Ja- ponica, and Spinta, grown in hot-houses at AVest Farms. N. Y. The larva is a "^fuarter of an inch long. The following genera belong to the subfamih' l^mplirc- (lonince : The genus Stigmtis, as its name indicates, may at once be known bj^ the very large pterostigma, as well as the unusually small size of the species. The body of the larva is moderately long and slender, cylindrical, tapering slowly towards both ex- tremities. The rings are short, very convex, subacutely so. and the larva is of a beautiful roseate color. iStigmus frater- iius Sa}' burrows in the stems of the Syringa, of Avhich speci- mens have been receiAcd from Mr. Angus with the larvae and l)upiTe. lu Cemonus the front narrows rapidly towards the insertion of the mandibles, and there is a short triangular enclosure on the propodeum, while the abdomen is shorter and thicker than in Peiuphredon, a closely allied genus ; the pedicel is also longer. The larvre of Cemonus inornatus Harris live in irregu- lar burrows in the elder, like those of Rhopalum from which they have been reared by Mr. Angus. They are knoAvn by the l)road flattened head and body, serrate side and tergum of the body, and large, conspicuously bidentate mandibles, as well as l)y the peculiarly flattened abdominal tip. In Passalcpcus the labrum is very prominent, while the man- dibles are ver}' large, widening towards the tip, and in the com- mon P. mcmdibidaris Cresson they are white, and thus very conspicuous. Tliis species burrows in company with the other wood-wasps mentioned above in the stems of the elder and syringa. The cells are lined with silk. The wasps appear early in June. Their nests are tenanted by Chalcids. The female stores her cells with Aphides, as we have found them :d)undantly in stems of plants received from Mv. Angus. The genus Pse)i seems to be a degraded Cerceris. but the 11 162 HYMENOPTEE A . iibdomGu is pedieelled, and ditiers from Mimesa^ a still more slender-bodied genus, in having the tip of the abdomen more or less grooved, while in Mimesa it is flat and not grooved at all. Psen leucopus Say has a dense silvery pile on the front of the head, with black antenna^, and the pedicel is rather short. Nyssonid^ Leach. In tliis family the head is transversely longer and less cubical than in the preceding group ; the ver- tex is liigher and more convex, while the front is narrow, the clypeus long and narrow, the eyes long and narrow, and the antennas are more clavate than in the Crabronidce, and the propodeura is sometimes armed with acute spines, while the enclosed space is smootiily i)olished or striated. The wings are long and narrow, and the abdomen is sessile in the typical genera, where it is obconie, but clavate when pedicellate. In Trijpnxiilon the body is long, with a pedicellate clavate abdomen. In Europe "Mr. Johnson has detected it frequent- ing the holes of a post pre-occupied by a species of Odynerus. and into which it conveyed a small round ball, or pellet, con- taining about fifty individuals of a species of Aphis ; this the Odynerus, upon her return, invariably turned out, flying out with it, held by her legs, to the distance of about a foot from the aperture of her cell, where she hovered a moment, and then let it fall ; and this was constantly the case till the Trypoxvlon liad suflScient time to mortar up the orifice of the hole, and the Odynerus was then entirel}- excluded ; for although she would return to the spot repeatedly, she never endeavored to force the entrance, but flew off to seek another hole elsewhere." T. politum Sa}^ has purplish wings, and no enclosure on the propodeum. T. fi-ir/idum Smith lives in the stems of Syringa, from which it has been reared by Mr. Angus. The thin, delicate cocoon is long and slender, enlarging slightly towards the anterior end. The genus MeUinus (belonging to the third subfamily, 3Ie1- h'nina',) is known by its broad front, and slender antennjv, and its pedunculate abdomen, while in Alyson, a slender- bodied genus, it is sessile. 3IelJim(s bivtaculatus Say has a black head, with pale tipped antenuiv, and two ovate yellow spots on the abdomen. Ahjson opjiositus is black, with two NYSSONID.E. 16" cellow spots on the altdomeii, which lias the liasal ring yel- lowish red in the female. The fourth subfamily is the Ni/ssonincp, so named from Nys- son, a typical genus. The genus Gorytes is trul^' a mimetic form, closely simulat- ing the genus Odynerus, one of the Vesjiciricp . The front of the head is narrow, while the cl^-peus is larger than usual. The species are numerous, occurring late in the summer on the flowers of Spinea. Gorytes Jiavicornis Harris is polished russet brown, with narrow yellow rings on the abdomen, the propo- deura is smooth and polished, and the basal ring of the abdomen is black. A species has been observed in Europe protruding her sting into the frothy secretion of Tettigonisie liAing on grass, and carrying off the insect to provision its nest with. Oxybelus is a short, stout, black genus, with whitish abdomi- nal spots, and stout spines on the thorax, while the sessile abdomen is distinctly conical. "Its prey consists of Diptera. which it has a. peculiar mode of carrying by the hind legs thr^ while it either opens the aperture of its burrow or else forms a new one with its anterior pair. Its flight is low, and in skii)s ; it is very active." (AVestwood.) Oxybelus emarginahfs Say has two oval membranous appen- dages to the metathorax, and is a common black species found abundantly on the flowers of the Virginia Creeper. In Nysson the body is a little longer, narrow compared with Miat of Oxybelus, while the terminal joint of the antennaj is Jiickened, flattened, and excavated beneath. Nysson laferah's Say is dull black, with six light spots on the abdomen. The species of Stizus are of large size and easily recognized by their hirsute body, stout legs, triangular silvery clypeus. and the high transverse vertex of the head. The propodeuni has a faintly marked triangular enclosure. The species are very rapacious, paralyzing grasshoppers and other large insects with their formidable sting, and carrying them off" to provision their nests. Professor S. Tenney has sent us a specimen of the Dog-day Cicada (C. canicularis) which Stizus sjyeciosus had thus stung. Mr. Atkinson has observed the same fact, and has found the deep burrows of this species, the hole being three- fourths of an inch in diameter. He has observed it feeding on sap running from a tree. 104 HYMENOPTEKA. The species of Larra are smaller, and ditfer from those of .Stizus in the long, narrow, very prominent labrum, the shorter (d^'peus, broader front and longer abdomen, the tip of which is withont the broad subtriangular area which is present in Stizus and the other genera of this family. Larra nnicincta Say is black- ish, with a single reddish band on the second abdominal ring. Be.'^ibecid^ Latreille. We have l)ut two genera, Benihex and 3Ioneclnla, which have large keads and flattened bodies, l)earing a strong resemblance to Syrphus flies from their similar coloration. The labrum is very large and long, triangular, lilie a beak. The species are very active, flying rajjidly about flowers with a loud hum. '•'The female Bembex burrows in sand to a considerable depth, burying various species of Dip- tera (S^a-phida^, Muscida^ etc.), and depositing her eggs at the same time in company Avith them, upon which the larvae, when iiatched, subsist. When a sufficient store has been collected, tiie parent closes the mouth of the cell with earth." " An anonymous correspondent in the Entomological Magazine, states that B. rostrata constructs its nests in the soft light sea-sands in the Ionian Islands, and api^ears to catch its prey (consisting of such flies as frequent the sand ; amongst others, a bottle- green fly) whilst on the wing. He describes the mode in which the female, with astonishing swiftness, scratches its hole with its forelegs like a dog. Bembex tursafa, according to Latreille, provisions its nests with Bombylii.'" (Westwood.) Dufour states that two Diptera, Panopea carnea and Toxophora fasciata, the latter allied to Systrophus, are parasites on Bem- bex. Mr. F. G. Sanborn has noticed the exceedingly swift flight of our common Bembex fasciata. Fabr. on sandy beaches where it is found most abundantlj-. Monedula differs from Bemliex in its slendtirer body, more chaate antennje, and its shorter, very obtuse labrum. The body is smoother, and most generally more higlily colored and more gaily spotted than in Bembex. Monedula Carolina Fal)r. and M. A-fasciata Say are common southwards of New England. Larrid.e Leach. Mr. F. Smith defines this family as having '•mandibles notched exteriorly near the base ; the labrum con- LARRID^. 165 cealed, with a single spine at the apex of the intermediate tibiie ; tlie abdomen is ovoid-conical." The genus Asfata is a large hairy form, with long antenna' and palpi and an elongated prothorax. Its spiny legs show its near rehitionship to the >S'p k eg idee. Astata unicolor Say repre- sents the genus in this country. Tachytes is also of larger size than the following genus. It is covered with long dense golden short hairs, with a trap- ezoidal front. Tachytes auruJentus Fabr. is rare; it frequents the flowers of the Asclepias, as we have found pollen masses at- tached to the spines of its legs. ' We figure (89) a tarsus of a wasp belonging probabl}^ to this genus, received from Mr. V. T. Chambers, showing the pollen masses of Asclepias at- tached to the spines. The genus in rrada "contains those species which have the marginal cell truncated at the apex and appendiculated, and three submarginal cells, the first as long as the two following ; .... the metathorax [propodeum] truncated posteriorly, elongate, the sides being generally parallel ; the mandibles are large and arcuate, t^:- 89. with a tooth on their exterior towards the base ; abdomen ovate-conical, acuminate at the apex." Larrada nrgentata Beauv. is covered with silvery- pile. It is a slender form, Avitli short, nearly unarmed legs. A Brazilian species of Larrada, according to Mr. H. "\V. Bates, builds a nest composed apparenth' of the scrapings of the woolly texture of plants ; it is attached to a leaf, having :i close resemblance to a piece of German tinder, or a piece of sponge. The cocoons Avere dark brown, and of a brittle consist- ency. The reporter, Mr. F. Smith, adds : "I am not aware of any similar habit of building an external nest having been pre- viously recorded ; our British species of the closely allied genus Tachytes, are burrowers in the ground, particularly in sandy situations ; their anterior tarsi are strongly ciliated, tlu^ claws bifid and admirably adapted for burrowing. On examin- ing the insect which constructed the nest now exhibited, I find the legs differently armed; the anterior pair are not ciliated. 1 GG H VM EXOPTERA . and the claws ave siiaple and slender, elearhf indicative of a [)ecnliar habit diltVring from its congeners, and liow admirably is this illustrated in the nest before us?" SpHEGiD^ Latreille. Smith defines this family as having ^•the posterior margin of the prothorax not prolonged back- wards to the insertion of the wings, and anteriorly produced into a neck, with the abdomen petiolated." The very fossorial legs are long and spiny, the posterior pair being of unusual length. The mandibles are large, curved, narrow, and acute, the base not beuig toothed externally, and the antennae are long and filiform. The species are often gaily colored, being ornamented with black and red, brown and red, or are entirely black, or blue. The}- love the sunshine, are very active, rest- less in their movements, and have a powerful sting. The sting of these and other wasps which store up insects for their young, penetrates the nervous centres and paralyzes the \ ictim without depriving it of life, so that it lives many daj-s. A store of living food is thus laid up for the young wasp. After being stung the caterpillars will transform into chrys- alids, though too weak to change to moths. Mr. Gueinzius, who resides in South Africa, observes that "•large spiders and caterpillars became immediately motionless on being stung, and I cannot help thinking that the poisonous acid of Hymen- (>[)tera has an antiseptic and preserving property ; for cater- pillars and locusts retain their colors weeks after being stung, and this, too, in a moist situation under a burning sun." These insects either make tlieir nests in the sand, or, like the succeeding family, are "mud-daubers," building their cells of nuid and plastering them on walls, etc. The tropical genus Ampulex is more closel>' allied to the preceding family than the other genera. The species are l)rassy green. Dr. (1. A. Perkins has described in the Ameri- can Naturalist, vol. 1, p. 293, the habits of a wasp, probabh' the Ampulex Sihirica Fabr., which inhabits Sierra Leone, and oviposits in the body of the cockroach. The dead bodies of the cockroaches are often found with the empty cocoon of the wasp occupying the cavity of the abdomen. A species of this genus, abundant at Zanzibar at certain sea- SPHEGID.E. IC? sons, was frequently observed by Mr. C. Cooke to attack the; cockroach. Tlie cockroacli, as if cowed at its presence, im- mediately yields without a struggle. The Anipulex stings and paralyses its victim, and then flies away with it. Chlorion is closely allied, containing blue and metallic green species, often with golden yellow wings. Chlorion cyaneum Dahlb., a blue species, is found in the Southern States. Tlie genus Priononyx "difiers from the genus Spliex in hav- ing the claws quadridentate beneath at their base ; the neui-a- tiou of the wings and the form of the abdomen are the same as in Harpactopus^'' which is found only in the tropics and Aus- tralia. Priononyx Thomce is found from South Carolina to Brazil, including the AVest Indies. The genus Sjjhex is quite an extensive one. The head is as wide as the thorax ; the antennae are filiform, mandibles large and acute, bidentate within, the teeth notched at their base, forming a rudimentarj- tooth, the apical tooth being acute. The thorax is elongate-ovate, truncated behind, with a trans- verse collar (prothorax). The fore wings have one marginal and three submarginal cells ; the marginal cell elongate, rounded at its apex ; the first submarginal cell as long as the two following. The abdomen is pedun- culated, conically ovate, and the an- terior tarsi are cili- ated in the females. Spliex ichneumo- nea Linn. (Figure 90) is a large rust- red species, with a dense golden pu- rig. 90. bescence. It is common from Massachusetts sonthAvards. In the last week of Julv, and during August and early in Sep- tember, we noticed nearly a dozen of these wasps busily en- gaged in digging their holes in a gi-avelly walk. In previous seasons they were more numerous, burrowing into grassy 1G8 IIVMENOl'TEUA. banks near the walk. Tlie holes were four to six inches deej). In beginning its hole the wasp dragged away with its teeth a stone one half as large as itself to a distance of eight inches from the hole, wliile it pushed away others with its head. In ])eginning its burrow it used its large and powerful jaws almost entirely, digging to the depth of an inch in live minutes, com- pleting its hole in about half an hour. After having inserted its head into the hole, where it loosened the earth with its jaws and threw it ont of the hole with its jaws and fore legs, it would retreat backwards and push the dirt still farther back from the mouth of the cell with its hind legs. In cases where the farther progress of the work was stopped by a stone too large for the wasp to remove or dig around ^ it would abandon it and begin a new hole. Just as soon as it reached the required depth the wasp flew a few feet to the adjoining bank and falling npon an Orchelimum vulgare or O. gracile, stung and paralyzed it instantly, bore it to its nest, and was out of sight for a moment, and while in the bottom of its hole must have deposited its egg in its victim. Reappearing it be- gan to draw the sand back into the hole, scratching it in quite briskly by means of its spiny fore tarsi, while standing on its two hind pairs of legs. It thus threw in half an inch of dirt upon the grasshopper and then flew off. In this wa}' one Sphex will make two or three such holes in an afternoon. The walk was hard and composed of a coarse sea-gravel, and the rapidity Avith which the wasp worked her way in with tooth and nail was marvellous. Sphex tibialis St. Fargeau is a black, stout, thick insect. Mr. J. Angus has reared this species, sending me the larvj-e in a cavity previously tunnelled by Xylocopa Virginica in a pine board. The hole was six inches long, and the oval cylin- drical cocoons were packed loosel}', either side by side, where there Avas room, or one a little in advance of the other. The interstices between them were fllled with bits of rope, which had perhaps been bitten up into pieces by the wasp itself; whilr the end of the cell was filled for a distance of tw^o inches with a coarse sedge arranged in layers, as if rammed in like gun- wad- ding. The cocoons are eighty to ninety hundredths of an inch long, oval lanceolate, somewhat like those of Pompilus. They SPIIEGID.E. IGii consist of two layers, the outer \Qvy tliin. tlie inner tough, parchment-like. The larvie hybernate and turn to pupa3 in the spring, appearing" in the sunnner and also in the autumn. The larva is cylindrical, Avith the pleural ridge prominent, and with no traces of feet ; the head, -which is small and not prominent, and rather narrow compared with that of Pelopscus, is bent inwards on the breast so that the mouth reaches to the sternum of the fourth abdominal ring. The posterior half of each ring is much thickened, giAing a, crenulated outline to the tergum. The abdominal tip is obtuse. S]:>hex Lanierii Guerin, according to Smith (Proceedings of the Entomological Society of London, Feb. 7, 1859), con- structs its nest of a cottony substance, filling a tunnel formed by a large curved leaf. The species of the genus are sup- ])osed to burro w^ in the ground, and the two cases aboAC cited show an interesting divergence from this habit. IMr. Smith adds, that in "the Sphex which constructs the nest in the rolled leaf, the anterior tarsi are found to be very slightly ciliated, and the tibiae almost destitute of spines, thus aflbrding another instance proving that difference of structure is indica- tive of difference of habit." The genus Pelopoixis is of a slighter form than in Sphex, the body being longer and slenderer ; the clypeus is as broad as long, triangular above, in front convex, or produced and end- ing in two teeth. The outer costal cell is lanceolate oval, the second subcostal cell subtrapezoidal, being Avidest above ; it is also somewhat longer than broad. The first median cell is very long and narrow, much more so than usual. The pedicel of the abdomen is long, the first joint in the male being often as long as the remainder of the abdomen. The larva of P. cmriileus Linn, is much like that of Sphex, having a cylindrical body with the rings thickened posteriorly. It differs from that of Pompilus in its longer and narrower head, the short broadly trapezoidal clypeus, and the distinctl}' marked exserted labrum. The mandibles are long and tridentate. The pupa (of P. flavipes) differs from that of the Vesx>ario' in having the head more raised from the breast ; the palpi are not partially concealed, as they may be easil}^ seen for their whole length. The long curved mandibles cover the base of the 170 HYMENOPTERA. maxilkxj and lingua, and the antenna^ reach to the posterior coxa?. The maxilhe are slender, not reaching to the tip of the labium. The female usually provisions her cells (Plate 5, Fig. 14) with spiders. The cells are constructed of layers of mud of unequal length, and formed of little pellets placed in two rows, and di- verging from the middle. The}' are a little over an inch long, and from a half to thi-ee-quarters of an inch wide, and are some- what three-sided, the inner side next the object, either stone- walls or rafters, to Avhich it is attached, being flat. As the earthen cells sufficientl}' protect the delicate larvie within, the cocoons are ver}^ thin, and brown in color. The cells of PeJojKeus flacipes from Brownville, Texas, col- lected l\v an United States otficer and presented to the Boston Society of Natural History, contained both spiders and niimer- ous pupte of a fly, Sarcophaga nucUpennis Loew (MS) which is somewhat allied to Tachina. These last hatched out in mid- summer a few days before the specimens of Pelopai-us. It is most probable that they were parasitic on the latter. These specimens of P. flavipes were more highly ornamented with yel- low than in those foimd northwards in the Atlantic States, the metathorax being crossed by a broad j^ellow band. The genus Ammophila is a long slender form, with a petio- late abdomen, the tip of which is often red. The petiole of the abdomen is two-jointed, and very long and slender, being longer than the fusiform part. In the males the petiole is in some species much shorter. The wings are small, with the apex more obtuse than usual ; the second subcostal cell is pentag- onal, and the third is broadly triangular. "Westwood states that "the species inhabit sandy districts, in which ^1. sabidosa forms its burrow, using its jaws in bur- rowing ; and when they are loaded, it ascends backwards to tiie mouth, turns quickly around, flies to about a foot's distance, gives a siidden turn, throwing the sand in a complete shower to about six inches' distance, and again alights at the mouth of its burrow." ''Latreille states that this species provisions its cells with caterpillars, but Mr. Shuckard states that he has observed the female dragging a verj^ large inflated spider up the nearly per- pendicular side of a sand-bank, at least twenty feet high, and I'OMI'ILID.E. 171 tliat whilst burrowing it makes a loud whirring buzz ; ami, in the Transactions of the Entomological Society of London, he states that he has detected both ^i. sabidosa and A. hirsnta dragging along large spiders. Mr. Curtis observed it bury the caterpillars of a Noctua and Geometra. St. Fargeau, how- ever, states that ^1. subidofia collects caterpillars of large size, especially those of Noctuse, with a surprising perseverance, whereas A. arenaria, forming a distinct section in the genus, collects spiders." (Westwood.) Ammophila cementaria Smith, and ^1. urnaria Klug, are the more common species in this country ; they are red and white, while A. luctuosa Smith is a black, shorter, stouter, more hirsute; species. They may all be seen flying about hot sandy places, and alishtins: near wells and standins; water to drink. PoMPiLiD.E Leach. In this famil}* the bod}' is oblong, the sides often compressed, and the head shorter, Avhen seen from above, being more trans- versely ovate than in the preceding famih'. The antennae are long, not geniculate, and in the males are stouter and with shorter joints than in the females. The eyes are narrow oval, and the maxillary palpi are six, and the labial palpi four-jointed. The prothorax is ex- tended on the sides back to the base of the wings, which latter are large and broad, the fore pair having three subcostal cells. The legs are very long and slender, with thick slender sprues. The Pompilidoi, of which about seven hun- dred species are known, have a wide geographical range, from the temperate zone to the tropics. Like the Sjihegidoi, they oviposit in the body of other insects, storing their nests, usually built in the sand, with spiders and caterpillars. The head of Pompilus (Fip;. 91) is a little longer, seen from HYMEXOI'TKUA. ubove, than in the other genera ; the front of the head is about a third longer than broad. The antennfc are long and fili- form and sometimes crenulate, as in Figure 91 a, in the males ; the mandibles are stout, broad, sabre-shaped, being much curved, with low flattened teeth, and the maxillary palpi are longer than the labial palpi. Tlu'' wings are rather broad, with the three subcostal cells lying in a straight row. The abdomen is slightl}-^ com- pressed, and equals in length the remainder of the body. The sting is very large and formidable, and ex- cessively painful, benumbing the parts it enters. They are exceediugl}^ active, running and fl^'ing over sandy places like winged spiders. There are about five hundred species of this genus described. They are usually shining black or deep bluish black, with Fig. !)1 a. Fig. 92. smoky or reddish wings, and sometimes a reddish abdominal band. This genus is interesting, as affording in its form a mean between the globular thorax and short body of the jlpiarim and the elongated body of the Ichneumonidce. The Fompilus fotynosus Say (Fig. 92), called in Texas the Tarantula-killer, attacks that immense spider the Mygale Henfzii, and, according to Dr. O. Lineecum (American Naturalist, IMav, rO.MI'ILID.E. 1" l.S()7), paral3-zcs it with its formidable sting, ami iuseiling an egg in its body, i)laces it in its nest, dug to the depth oC five inches. There is but a single brood, ]) reduced in June, wliich is killed off by the frosts of November. This species feeds iu summer "upon the honey and pollen of the flowers of the Elder, and of Vitis ampelojwis, the Virginia Creeper ; but its favorite nourishment is taken from the blossoms of Asdepias qiiadri folium.'" P. cyJindncus Cresson (Fig. 03, wing) is one of Tig. 94. ( Lincecura.) our smallest species, being from three to five lines long. It occurs in the South and West. P. arctus Cresson (Fig. 94, wing) in- habits Colorado Territory. J\ Marim Cresson (Fig. 95, ? enlarged) is a beautiful and rare species found in Peimsylvania. The genus Priocnemis is characterized by the two hind pair of tibiiie being serrated ( 5 , Fig, 96, a, wing ; h, pos- terior leg ; c, anterior leg), and by the want of spines on the an- terior legs. P. unifasciatas Say is a wide-spread species and readily recognized b}^ the deep blade color of the body, the yellow an- tennae and the large yellow spot at the tip of each anterior wing. The genus Agenia (Fig. 97, a, wing ; b, posterior leg) differs in having smooth legs. ^1. brevis Cres- Fig. 96. son (Fig. 98, wing) is a little spe- cies found in Georgia. A. congruus Cresson (Fig. 99, wing) u as captured in West Virginia ; and A. accejytus Cresson (Fig. 100, wing) in Georgia. The genus Notocyplma (Fig. 101. ?, wing) is found in Brazil and Mexico. Planicepa (Fig. 102, 174 HYMEXOriElIA. wmg) contains a few species, of which P. niger Cresson, an entirel}' black species, is found in Connecticut. Aporus (Fig. 103, wing) contains a single American species, A. fasciatus Smith, taken in North Carolina. From Mr. F. G. Sanborn we have re- ceived the larva and cocoon of PompUos fanerens St. Farg., a small black spo- The larva is short and b -, Fig. 97. cies, which builds its nest in fields broad, with the lateral region rather prominent, and the tip of the abdomen rather acute. It differs from Pelopseus in its stouter, rather flat- tened bod^', and thickened segments, though as our specimen is preserved in alcohol these characters may have be- come exaggerated. It more nearly re- sembles Pelopffius in its transverse clypeus, thin bilobate labrum, and the stout mandibles, which are, hoAvever, much stouter than in Pelopiieus, while the whole head is shorter, broader, and rounder. It is probable that this pecu- liar form of the head (which as in Sphex is bent beneath the breast), together Fig. 103. with the broad transverse clypeus, and broad, short, bilobate. thin, transparent labrum, and especially the unidentate short broad mandibles are family characters, sep- arating the larvae of this group from those of the Spli eg idee . The cocoon is ovate, long, and slender, much smaller at one end than the other, not being so regularly fusiform as in Sphex. Ceropales differs from the foregoing gen- Fiff. 100. era in its broad head, its much shorter ab- domen ; and also in the eyes being a little excavated, in the depressed labium, the narrow front, Avhich dilates above and below the middle, and in the greatly elongated hind legs, gen- erally banded with red or whitish. Ceropales bipuncfata Say is generally distributed throughout the United States. It SCOLIAD.E. 17. is easily recognized by the 1)lack bofl}^ and legs, and red pos- terior femora, and is six lines long. C. Rohinsonii Cresson (Fig. lOi, (?) is an elegant species found in West Virginia. An allied genus is Mygnimia (Fig. 105, wing) containing M. Mex- fcana Cresson and 31. ris- tuIata'Dahlb., two Mexican species. In the genus Pepsis (Fig. lOG, wing) the max- illary and labial palpi are of equal length. The spe- cies are large, some of them being among the lar- gest of Hymenoptera, and are generally indigo-blue in color. Fejjsis Jieros Dahlbom is found in Cuba; it is two inches long. P. ajanea Linn., which is blackish-blue, with blue abdomen and Avings, the latter reddish at the apex, has been described by Beauvois from the United States, while P. elegans St. Farg. also occurs in the Southern States. P. formosa Say affords another example of a species Fig. 106. common to both sides of the Rocky Mountains, as it has been found both in Texas and Cal- ifornia. It is black, with bluish or greenish reflections, with bright fiery red wings, and is thirteen to eighteen lines long. ScoLiAD.'E Leach. This family forms a group very easily distinguished from the Bembecidce or Chrysididce ., as well as the Po7npilidce, hy the broad front, the small indented eyes, and the great sexual differences in the antennae, those of the male being long and slowly thickened towards the tip, while in 1 7G 11 YM enoptp: n a . the female they are short, thick, and elbowed on the second joint. The cl}iDeus is large, irregularly quadrilateral, becom- ing shorter in the lower genera, and the labrum is small, scarcely exserted, while the mandibles are, in the female es- pecially, largo and broad. The prothorax is very square in IVont. In the fore-wings are three subcostal spaces. The abdomen in the typical genus (Scolia) is broad and Hat, longer than the rest of the body. The abdomen of Mutilla approaches that of the Clirysididai in having the second ring much en- larged over the others. The males usually have the anal stylets very prominent, Avliile the sting of the female is very powerful. The bod}' and legs are generally very hirsute, and the first tarsal joint is as long as the tibiiB. The genus Sapyga is easily recognized by its smooth slender body, being ornamented with yellow, with transverse bands on the abdomen. The head is long, very convex in front, and the antennae are clavate ; the prothorax is \QYy broad, giving an oblong appearance to the thorax. The legs ai'e slender and smooth. It is said to be parasitic, laying its eggs in the cells of Osmia. Scqiyga Martinii of Smith is found northward. The species of Scolia are often of great size, being black and very hirsute, with the labium composed of three linear di- visions ; the abdomen alone being banded or spotted with yellow on the sides. The^- are found in the hottest places about strongly scented flowers. In Europe,, Scolia hicincta ''makes its burrows in sand-banks, to the depth of sixteen inches, with a very wide mouth;" and it is probable that the nest is stored with grasshoppers. Scolia quadrimaculata Fabr. is found in the Middle and Southern States. The larva of Scolia flavifrons was found by Passerini to live in the body of the lamellicorn beetle, Oryctes nasicornis. In Madagascar, Scolia oryctoj)ha(ja lives on Oryctes simia, according to Coquerel. Professor Sumichrast states that at Tehuacan (Department of Puebla) the Scolia Azteca Sauss. is very conmion ; and is particularly abundant in the leather tanneries, which leads him to think that the females of this species also deposit their eggs under the epidermis of the larva which abounds in the tan. Tiphia is black throughout and rather hirsute. The antcnuiv MUTILLAUI.E. 177 are shorter than in Scolia or Myzine ; the chpeus is also .shorter, while the prothorax is longer. In the fore-wings the onter cos- tal cell is short, broad, angulated, oval ; and of the two sub- costal cells, the outer one is broad and triangular, twice as long as broad, while the first median cell is regularly short rhom- boidal, much more so than in the other genera. The females, according to Westwood, ''make perpendicular l)urrows in sandy situations, for the reception of their eggs ; but the precise food stored np for the larva; has not been ob- served." Tiphia inornata Say is a common species with ns, and flies low over sandy places earl}^ in the season. The short oval head, the large eyes, short meso-scutum, large meso-scutellum, and the flattened, rather smooth body, characterize the genus Mijzine. The females are very diflerent from the males, the two sexes being for a long time considered as separate genera. The female, especially, differs in the great length of the square prothorax, which is very broad and convex in front. In the male the eyes are lunate, while in the female they are small, entire, and remote. In its general form the fe- males much resemble Scolia, while the males are long and nar- row, with broad yellow bands, especially on the abdomen, and a large exserted sting-like organ. Myzine sexcincta Fabr. is seen from New England southwards, flying low over hot sandy places. The genus Elis is closely allied. Sumichrast (American Nat- uralist, vol. 2), surmises that Ells costaUs St. Farg. lives on certain Scarabaiides, which nndei'go their metamorphosis in the formicary of Q^codoma in Mexico, MuTiLLAKi.E Latreille. This interesting family is character- ized by the females alone being wingless, though Morawitz sa3-s that wingless males occur in two species ; and by the absence, generally, of the three ocelli. In Mutilla and Myrmosa the thorax is still high, compressed, and oblong cuboidal, and ex- cept in the closely united tergal pieces the females do not greatly recede from the type of the winged males. The species are very equal in size, are black, or black and red, and either smooth or hirsute. The antemiiB are inserted low down on the front, the cl3"peus being very short and broadly ovate (especially in ]Myrniosa), 12 178 HYMENOPTERA. or it is indented, as in Mutilla. The tongue is shorter than usual. The sides of the thorax contract in width, both before and be- hind. Tlie nieso-scutura is squarer tlian usual, while the meso- scutellum is much narrower and longer, and the propodeum is squarely truncated behind, thus presenting a full convex surface. The abdomen is not much longer than the rest of the body, be- ing shorter than usual. In all these characters this family shows its affinities to the Ants. The wings are very dissimilar in the dift'erent genera. In Myrmosa the neuration closely approaches that of 8apyga, while in the larger, more acute primaries of Mutilla, and especially in the short outer costal cell, and short open pterostigma, the latter genus differs from the others. The male of Scleroderma closely mimics the Procto- t r lip i d re , the veins of the wings being absent, while the form of the head and abdomen also reminds us of some genera in that family. The wingless female is very diiferent, having more of the form of Mutilla, with a large oblong head and long acutely conical abdomen. The species are minute and rarely met with. S. contracta Westwood is found in "Carolina." In the female Metlioca the eyes are very long, and the seg- ments of the abdomen are widely separated, nmch as in the ants. Metlioca Canadensis Smith is shin- ing black, and slightly villose. The species of. Myrmosa may be known by the very short clypeus, the broad ver- tex, and the rings of the a])domen of the ^ »- male being unusually contracted. The Fig. 107. abdomen of the female is cylindrical, about twice as long as broad, and thickest on the second ring. The rings are densely hirsute on the hinder edge. Miirmosa unicolor Say (Figs. 107, male ; 108, female) is widely distributed. We i have taken this species in Maine, while sex- j nally united, early in June. The wingless female is like an ant, and is pale reddish on the thorax and basal ring of the abdomen, and the antenna' and feet are concolorous, Avhile the head and remaining abdominal rings are much darker. It is .20 inch long. The male is .28 inch long and entirel}' black. FOKMICARI^. 179 The genus MutiUa is a very extensive one, and enjoys a wide o-eographical range. It is througliout stouter than Myrmosa, the head is more cubical, and the thorax and abdomen is shorter, the tip of the latter being somewhat truncated. The wingless female closely resembles, both in its form and motions, a Avorker ant. The body is coarsely granulated and either naked or densely hirsute, and of a scarlet, black, or pale red, or brown-black color. The females are found running in hot sandy places, and hide themselves quickly when disturbed, while the males frequent flowers. MutUla occidentalis is a large species. It is of a beautiful scarlet color and is armed with a very powerful sting. According to Profes- sor A. E. Verrill this species was found b}" him, at New Haven, to construct deep holes in a hard beaten path, storing its nest with insects. This species is also said b}^ rig. lOo. Kirby to be very active, "taking flies by surprise." (West- wood.) Mr. Verrill noticed that this insect makes a slight creaking noise. The larvoe of M. Eiiwjxea are said to live parasiticall}' in Humble-bees' nests. MutiUa ferriujata Fabr. (Fig. 109) is found frequently in New England. FoRMiCARi.E Latreille. The family of ants w-ould seem naturall}' to belong with the trul}^ fossorial H^-menoptera, both from their habits and structure. Both males and females are winged, but the males are much smaller than the females, while the wingless workers are smaller than the males. In these wingless forms the segments of the thorax become more or less separated, making the body much longer and slenderer, and less compact than in the winged nor- mal sexual forms, the prothorax being more developed than in the males and females. The workers often consist of two forms : one with a large cubical head, or worker major, some- times called a soldier, and the usual small-headed form, or worker minor. The head is generally triangular. The eyes are large in the males, smaller in the workers, and in those of some genera (Ponera, Typhlopone, etc.) they are absent ; while in tlie 180 HYMENOPTEKA. workers the ocelli are often wanting, though present in the winged individuals ol" both sexes. The antennae are long, slender and elbowed. The mandibles are stout, and toothed, though in those species that do not themselves labor, but en- slave the workers of other species, the}^ are unarmed and slender. The maxillarj^ palpi are from one to six-jointed, and the labial palpi two to four-jointed. The fore-wings usuall}- have but a single complete subcostal (cubital) cell. The sling is often present, showing that in this respect as well as their fossorial habits the ants are truly aculeate llymenoptera. The larva is short, cylindrical, with the end of the body obtuse. The rings of the body are moderatel}' convex. The head is rather small and bent upon the breast. The larvae are fed by the woi'kers with food elaborated in their stomachs. The larva) of the stingless genera usually s[)in a delicate silken cocoon, while those of the aculeate genera do not. Both Latreille and Westwood, however, state that sometimes, as in Formica fusca, of Europe, the pupa; are naked, and at other times enclosed in a cocoon. The colonies of the different species Aary greatly in size. In the nests of Formica scoKjuinea the luimber of individuals is Aer^' great. The history of a formicarium, or ant's nest is as follows : The Avorkcrs only (but sometimes the Avinged ant;) hibernate, and are found early in spring, taking care of the eggs and larva) produced by the autumnal brood of females. In the course of the summer the adult forms are developed, swarming on a hot sultry day. The little jelloAV ants, abundant in paths and about houses in Ncav England, generally swarm on the ai- ternoon of some hot day in the lirst Aveek of September, when the air is lilled towards sunset Avith myriads of them. The females, after their marriage lligiit in the air, may then be seen entenng the ground to lay their eggs for ucav colonies, or, as Westwood states, they are often seized b}' the workers and retained in the old colonies. Having no more use for their Avings they pluck them oil', and may be seen running about Avingless. According to (ilould, an early English obserAcr. the eggs destined to hatch the future females, males and workers, are deposited at three diUcrent [xriods. The nests of some species of Formica are six feet in diameter FOKMICAIJI^. 181 and contain many thousand individuals. Ants also build nests of clay or mud, and inhabit hollow trees. They enjoy feeding upon the sweets of flowers and the honej^ of the Plant- lice, which they domesticate in their nests. Several species of beetles, including some of the Stapliylinidoe^ take up their abode in ants' nests. Ants are useful as scavengers, feeding on decaj'ing animal matter. A good method of obtaining the skeletons of the smaller animals, is to place them on a densely populated ant-hill. The habits of the ants, their economy and slave-making habits, are described in the Avorks of Huber, La- treille, and Kirby and Spence. Upwards of a thousand species of ants have alread}' been described ; those of this countr}' have still to be monographed. The first group of this extensive familj^ consists of Dorylus and its allies, and Formica and the neighboring genera, all of which are distinguished b}' having only the first abdominal seg- ment contracted, while in the second group {Myrmicarioe) , the two basal rings are conti'acted into knot-like segments. The genus Dorylus was, by Latreille, King, and others, in- cluded in the Mutillarim . The head is very short, the ocelli are large and globular. The thorax and abdomen are elongated, the last is cylindrical, with a small, round, basal joint. Tiie legs are short, with broad compressed femora and feather-like tnrsi. In the wings the outer subcostal cells are wanting. The females are not Aet known. Mr. F. Smith says that Dorylu;; was found by Hon. "W. Elliot to live in the man- ner of ants, under the stone foundation of a house in India. The society was very numerous. The diflerence in size of the male and Avorker is very remarkable. The males are of large size and are found in tropical Asia and Africa. TypMopone is an allied genus. T. j)a?Z?})es Haldeman is found in Pennsjdvania. To the genus Anomma belong the Driver-ants of "Western Africa. They march in vast armies, driving everything before them, so formidable are they from their numbers and bite, though they are of small size. The}' cross streams, bridging them b}' their interlocked bodies. Only the w^orkers are known. Two species only, A. Burmeisteri Shuckard, and A. arcens Westwood, are described from near Cape Palmas, West Africa. 182 HYMENOPTERA. The genus Ponera is found distributed tln-oughout the tropics. The females and workers are armed with spines ; tlie abdomen is elongated, the segments more or less diminished in size, the first comparatively large and often cubical. The legs are slender. P. fcrniginea Smith is a Mexican species. The allied genus Odontomadms springs like some leaping spiders. It uses for this purpose its xinusually long mandibles, which are bent at right angles. O. darus Roger lives in Texas. Formica includes the typical species of ants. Over two hun- dred species of this genus have been already described. The body is unarmed. The abdomen is short, oval or spherical, the scale-like first segment being lenticular in form, with a sharp upper edge. The subcostal cell of the fore-wings ends in a point. Formica sanguinea Latr. is one of our most abundant species, making hillocks of sand or claj^ , according to the nature of the ground. From the formicary walks, and underground galleries, radiate in all directions. This species has been ob- served making forays upon each others colonies. We ha^e found a variet}' of this species in Labrador, where it is com- mon. It does not throw up iiillocks, but tunnels the earth. This species has been observed in Euro})e by P. Iluber, to go on slave expeditions. They attack a ''negro-colou}- " be- longing to a smaller black species, pillaging the nest, and carry- ing off merely the larvae and pupge. The victors educate them in their own nests, and on arriving at maturity the negroes take the entire care of the colony. Pohjergus rufescens is also a slave- making ant, and "Latreille very justl}' observes that it is physi- cally impossil)le for the rufescent ants {Polyergus rufescens). on account of the form of their jaws, and the accessory parts of their mouth, either to prepare habitations for their famil}-, to procure food, or to feed them." Formica sanguinea sallic;; forth in immensely long columns to attack the negro ant. Ilu- ber states that only five or six of these forays are made within a period of a month, at other seasons thej^ remain at peace. Huber found that the slave-making Pohjergus rufescens when left to themselves perish from pure laziness. They are Avaited upon and fed by their slaves, and when they are taken awaj-, their masters perish miserably. Sometimes they are known to laboi . and were once observed to carry their slaves to a spot chosen FORMIC ARI.E. 183 for a nest. The F. sanguiuea is not so helpless, "they assist their negroes in the construction of their nests, they collect their sweet fluid from the Aphides ; and one of their most usual occupations is to lie in wait for a small species of ant on which they feed ; and when their nest is menaced by an enemy they show their value for these faith- ful servants, by carr^'ing them down into the lowest apartments, as to a place of the greatest security." (Kirby.) Pupae of both of the slave- making species were placed in the same formicary by Huber, where they Fig. no. were reared by the "negroes," and on arriving at maturit}' "lived together under the same roof in the most perfect amit}'." as we quote from Kirby. Darwin states that in England, F. sanguinea does not enslave other species. In this country Mr. J. A. Allen has described in the Proceedings of the Essex Institute, vol. 5, 1866, a foi'ay of a colony of F. sanguinea upon a colony of a black species of Formica, for the purpose of making slaves of them. Formica Pensylvanica, our largest species, is found in oaks and decay- Fig. 111. ing trees, while F. herculanea Latr. burrows in the earth, its hole opening beneath stones and sticks. Gould, who wrote in 1747, states that there are two sizes of workers of the common European Formica rvfa, and jlava ; one set of individuals exceeding the other by about one-third. Kirby states that in his specimens "the large Avorkers of For- mica riifa are nearly three times, and of F. Jlava, twice the size of the small ones." Mr. E. Norton describes F. fulvacea (Fig. 110, worker minor), and also Tajyinoma tomentosa (Fig. Ill, worker major; antemne broken off), from Mexico. The tropical genus Polyrhacliis includes, according to Smith, all those species that closely resemble Formica, but which 184 HYMENOPTEEA. Fi-. 112. have the thorax and node of the peduncle armed with spines or hooks. They construct small semicircular nests, of a kind of net-work, on the leaves of trees and shrubs. Their communities are small, sel- dom exceeding twenty individuals. Mr. Norton describes P. arboricola (Fig. 112, worker major) from Mexico. An allied genus is Ectatomma (Fig. 113, worker major of E. ferruginea Norton, from Mexico). Mr. F. Smith has described a new genus, (EcojjhyUa, which is allied to Formica. They are green ants, found building in trees in the tropics of the old world. The nest of (E. smaragduta Smith is "formed by drawing together a number of green leaves, which they unite with a fine web. Some nests are a foot in diameter. They swarm, says Mr. AVallace, in hilly for- ests in New Guinea. Their sting is not very severe. This genus forms a link between Formica and Myrmica ; it agrees with the former in hav- ing a single node to the pe- duncle, and with the latter in haviug the ocelli obsolete in the workers, and in beiug fur- nished with a sting." The curious Iloney-ant of Texas and Mexico, Myrmeco- cystus Mexicanus Westwood, has two kinds of "workers of Yery distinct forms, one of the usual shape," according to Smith, " and performing the ^'S- 113. active duties of the formica- rium ; the other and larger worker is inactive and does not quit the nest, its sole purpose, apparently, being to elaborate a kind of honey, which they are said to discharge into prepared recep- tacles, which constitutes the food of the entire population of the community. In the honey-secreting workers the abdomen is distended into a large globose bladder-like form. From this honey an agi-eeable drink is made b}' the JNIexicans." FORMICARI^. 185 The second subfamilj^, JTyrmicarice, includes those species ill which the two first abdominal segments are contracted and lenticular. In Myrmica the females and workers are armed with spines, and the ocelli are absent in the workers. The species are very small, and mostly bright colored. Myrmica molesta Say is found in houses all over the world. G. Lincecum describes the habits of the Agricultural Ant of Texas, Myrmica molefaciens. It lives in populous communi- ties. "They build paved cities, construct roads, and sustain a large military force." In a year and a half from the time the colony begins, the ants previously living concealed beneath the surface, appear above and "clear away the grass, herbage, and other litter, to the distance of three or four feet around the entrance to their cit}', and construct a pavement, .... con- sisting of a i^retty hard crust about half an inch thick," formed of coarse sand and grit. These pavements would be inun- dated in the rainy season, hence, " at least six months pre- vious to the coming of the rain," they begin to build mounds rising a foot or more from the centre of the pavement. Within these mounds are neatly constructed cells into which the "eggs, young ones, and their stores of grain, are carried in time of rainy seasons." No green herb is allowed to grow on the pavement except a grain-bearing grass, Aristida stricta. This grain, when ripe, is harvested, .and the chaff removed, while the clean grain is carefully stored away in dr^^ cells. Lincecum avers that the ants even sow this gniiu. Thej^ also store up the "grain from several other species of grass, as well as seeds from many kinds of herbaceous plants." Pheidole is distinguished by having workers with enormous heads. P. notabiUs Smith, from the Island of Bachian, Indian Archipelago, is noted for the enormously enlarged, cubical head of the worker major, which is at least six times the size of the abdomen, while in the worker minor, the head is of the ordinary size. An Indian species, P. providens Westwood, according to Col. Sykes, "collects so large a store of grass seeds as to last from January and February, the time of Iheir ripening, till October." The genus Atta is also well-armed, while the workers have a very large, deeply incised and heart-shaped head, without 186 HYMENOPTERA. ocelli, and the second abdominal knot-like ring is verj^ trans- verse. A. clypeata Smith is a Mexican species. In Eciton the man- dibles nearly equal the length of the in- sect itself. Tills ge- nus is the most ferocious of all the ants, entering the nest of species of Formica and tearing them, limb from limb, and then carrying olT the remains to their own houses. Eciton Mexiccma Roger (Fig. 114, worker major, o, front view of head, show- Fig. 114. ing the immense sickle-like mandibles, and only the two basal joints of the antennsB ; Fig. 115, worker minor, with a front view of the head, showing the mandi- bles of the usual size). This species, with Eciton Snmichrastl Norton, (Fig. 116, worker minor) has been found by Professor Sumichrast at Cordova and Orizaba, Mexico. The males of Eciton are not yet known. Smith supposes that Labidus (a genus allied to Dorjlus) is the male form, and Sumi- chrast tliinks this conjec- ture is "sustained by the fact that it is in the season when the sorties of the Eciton are the more frequent that the Labidus also show themselves." FORMIC ARIiE. 187 An allied genus is Pseudomyrma. P. bicolor Guerin (Fio-. 117) is found in Central America. P. flavidula Smith, found in Central and South America, in Mexico lives, accordino- to Sumichrast, within the spines which arm the stems of certain species of Mimosa. These spines, fixed in pairs upon the branches, are pierced near the end by a hole (Fig. 118 a), which serves for the entrance and exit of the ants. The genus (Ecodoma differs from Atta in having the thorax armed with spines. CE. Fig. iic. Mexicana Smith (Figs. 119, female; 120, worker major) is abundant on the Gulf Coast of Mexico. In many places, ac- cording to Sumichrast, the natives eat the females after hav- ing detached the thorax. The intelligence of these ants is wonderful. They are seen in immense imm- bers transporting leaA'es. Sumichi'ast states that "the ground at the foot of the tree, where a troop of these ' arrieras,' or workers, is assembled for despoil- ing it of its leaves, is ordinarily strewn \\'ith frag- ments cut off with the greatest precision. And if the Fig. 117. i^QQ jg j^Q^ ^QQ lofty, one can satisfy himself that a party of foragers, which have climbed the tree, occupies itself Avholly in the labor of cutting them off, while at the foot of the tree are the carriers which make the journeys between the tree and the nest. This manage- ment, which indicates among these « insects a rare degree of intelligence, is, perhaps, not a constant and in- variable practice, but it is an incon- testable fact, and one which can be constantly proved." "It is specially in the argillaceous countries that the OEcodomas build their enormous formicaries, so that one perceives them from afar by the projection which they form above the level of the soil, as well as by the absence of vegetation in their immediate neighborhood. These nests occupy a surface of many square 188 HYMENOPTERA. metres,* and their depth varies from one to two metres. Very mauy openings, of a diameter of about one to three in- ches, are contrived from the exterior, and conduct to tlie inner cavities which serve as storehouses for the eggs and larvae. The central part of the nest forms a sort of funnel, designed for the drainage of Avater, from which, in a country' where the periodical rains are often abundant, they could hardly es- cape without be- ing entirely sul)- merged, if they did not provide for it some out- let. "Tiie system which reigns in Fig. 119. the interior ol" these formicaries is extreme. The collection of ACgetable debris brought in by the workers is at times considerable ; but it is deposited there in such a manner as not to cauce any inconvenience to the inhabitants, nor impede their circulation. It is mostl}^ leaves which are brought in from v, ithout, and it is the almost exclusive choice of this kind of vegetation whicli malces the (Ecodoma a veritable scourge to agTiculture. At each step, and in almost cA'ery place in the elevated woods, as on the plains ; in desert places as well as in the neighborhood of hal)itati()ns, one meets numerous columns of these insects, occupied with an admirable zeal in tlie transportation of leaves. It seems even that the great law of the divi- sion of labor is not ignored by these little creatures, judging from tlie observations which I have often had occasion to make." (Sumichrast.) '•Tlie (I:J. cepludotes" says II. W. Bates, '"from its immense numbers, eternal industry, and its plunderinj?; i^ropensities, be- comes one of the most important animals of Brazil. Its immense hosts are unceasingly occupied in defoliating trees, and those most relished by them are preciseh' the useful kinds. They * A metre is about thirty-nine (39.37) inches. FORMICARI^. 189 have regular divisions of laborers, numbers mounting the trees and cutting oft" the leaves in irregularly' rounded pieces the size of a shilling, another rela}- carrying them off as they fall." "The heavily laden fellows, as they came trooping in, all de- posited their load in a heap close to the mound. About the mound itself were a vast number of workers of a smaller size. The very large-headed ones were not engaged in leaf-cutting, nor seen in the processions, but were only to be seen on dis- turbing the nest." Bates also says, "I found, after removing a little of the surface, three burrows, each about an inch in tUamet(;r ; half a foot downward, all three united in one tubular burrow about four inches in diameter. To the bottom of this I could not reach when 1 probed with a stick to the depth of four or live feet. This tube was perfectly- smooth and covered with a vast number of workers of much smaller size than those oc- cupied in conveying the leaves ; they were unmixed with any of a larger size. Afterwards, on probing lower into the bur- row, up came, one by one, several gigantic fellows, out of all proportion, larger than the largest of those outside, and which I could not haAC supposed to belong to the same species. Be- sides the greatly enlarged size of the head, etc., they have an ocellus in the middle of the forehead ; this latter feature, added to their startling appearance from the cavernous depths of the formicarium, gave them quite a Cyclopean character." Of another species, the (Ec. sexdentata, Mr. Smith quotes from Rev. Hamlet Clark, that at Constancia, Brazil, the pro- prietor of a plantation used everj- means to exterminate it and failed. " Sometimes in a single night it will strip an orange or lemon tree of its leaves; a ditch of water around his garden. which quite keeps out all other ants, is of no use. This spe- cies carries a mine under its bed without any difficulty. In- deed, I have been assured again and again, by sensible men, that it has undermined, in its progress thi'ough the country, the great river Paraiba. At any rate, without anything like a nat- ural or artificial bridge, it appears on the other side and con- tinues its course." This testimony is confirmed by Mr. Lincecum (Proceedings of Aca(]emy of Natural Sciences, Philadelphia, 1867, p. 24) in an interesting account of the GEc. Texioia, which he has observed for eighteen years. lie states 190 HYMENOPTERA. that they often carry their subterranean roads for several hun- dred yards in grassy districts, where the grass would prove an impediment to their progress. On one occasion, to secure ac- cess to a gentleman's garden, where they were cutting the vegetables to pieces, they tunnelled beneath a creek, which was at that place fifteen or twenty feet deep, and from bank to bank about thirty feet. He also observes that the smaller workers Avhich remain around the nest do not seem to join in cutting or carrying the leaves, but are occupied with bringing out the sand, and generally work in a lazy way, very differently from the quick, active leaf-cutters. Also, that the pieces of leaves are usually dried outside before being carried in, and that if wet b}^ a sudden shower are left to decay without. He also thinks that their lives are dependent upon access to water, and that the}'^ always choose places where it is accessible by digging wells. In one case, a well was dug by Mr. Pearson for his own use, and water found at the depth of thirty feet. The ant-well which he followed was twelve inches in diameter." Fig. 121. (Norton, American Naturalist, vol. 2.) The genus Cryptoceriis is remarkable for its flattened head, with the sides expanded into flattened marginal plates, con- cealing, or partly hiding the eyes. C. imiUispinosus Norton (Fig. 121) is the most common species about Cordova, Mexico, where they live, according to Sumichrast, within the trunks of trees. CiiRYSiDiD^ Latreille. In this small group the thirteen- jointed antennie are elbowed, the eyes are oval and the ocelli distinct. The maxillary palpi are five, and the labial palpi three-jointed. There are about four hundred species known. These insects are very different from the ants in their oblong- compact form, their nearly sessile, oblong abdomen, having only three to five rings visible, the remaining ones being drawn with- in, forming a long, large, jointed sting-like ovipositor, which can be thrust out like a telescope. The abdomen beneath is concave, and the insect can roll itself into a ball on being dis- turbed. Thej^ arc green or black. The sting has no poison- bag, and in this respect, besides more fundamental characters. CHRYSIDID^. 191 the Chrysis family approaches the Ichneumons. They best merit the name of "Cuckoo-flies," as they fly and run briskly in hot sunshine, on posts and trees, darting tlieir ovipositor into holes in search of the nests of other Hymenoptera, in which to lay their eggs. Their larvte are the first to liatch and devour tlie food stored up by other fossorial bees and wasps. "St. Fargeau, however, wlio has more carefully' examined tlie econ- omy of these insects, states that the eggs of the Chrj^sis do not hatch until the legitimate inhabitant lias attained the greater part of its growth as a larva, when the larva of the Chrysis fastens on its back, sucks it, and in a very short time attains its full size, destro3dng its victim. It does not form a cocoon, but remains a long time in the pupa state." (Westwood.) " In the Entomological Magazine has been noticed the dis- covery of Iledj^chrum bidentulnm, which appears to be parasitic upon Psen caliginosus ; the latter insect had formed its cells in the straws of a thatched arbor, as many as ten or twelve colls being placed in some of the straws. Some of the straws, per- haps about one in ten, contained one or rarely two, of the Hedychrum, placed indiscriminately' amongst the others. Walkenaer, in his Memoirs upon Halietus, informs us that Hedjxthrum lucidulum waits at the mouth of the burrows of these bees, in order to deposit its eggs therein ; and that when its design is perceived by the bees, they congregate together and drive it away. St. Fargeau states that the females of Hedychrum sometimes deposit their eggs in galls, while II. regium oviposits in the nest of Megachile muraria ; and he mentions an instance in which the bee, returning to its nearly finished cell, laden with pollen paste, found the Hedychrum in its nest, which it attacked with its jaws ; the parasite im- mediately, however, rolled itself into a ball, so that the Mega- chile was unable to hurt it ; it, however, bit off its four Aviiigs which were exposed, rolled it to the ground and then deposited its load in the cell and flew away, whereupon the Hedychrum, now being wingless, had the persevering instinct to crawl up the wall to the nest, and there quietly deposit its egg, which it placed between the pollen paste and the wall of the cell, which prevented the Megachile from seeing it." (Westwood.) In Cleptes the underside of the abdomen is not hollowed out ; 192 HYMENOPTEKA. it is acutel}' oval, and with five rings in tlie male. Cleptef, semiaurata Latr. is found in Central Europe. We have no na- tive species. In Chryms and the other genera, Stilbnni, Parno- pes, and Iledychruin, the abdomen is hollowed beneath, and the tip is broad and square. Chri/sis hilaris Dahlh. (Fig. 122) is a short, thick, bluish green species, .32 inch in length. It is not uncommon in New England. In Jledychrum the maxillary palpi and ligula are rather short, the last cordate ; the mandibles are three- toothed witliin. The abdomen is broad and short, almost spherical, the second seg- ment being the largest. H. dimidiatum Say is found in the Middle States. The European StilMim splendidum, Fabr. according to Du- fom-, lives in the cells of Pelopajus spirifex. It makes oblong ' <»>'~X£"-^ ., cocoons of a deep brown, with rounded ^ ^^f(—^i^' ^ — -. ends ; they are of great tenacity, being mixed with a gummy matter. Mr. Guenzius states that in Port Natal "a species of StUhiim lnys its eggs on the collected caterpillars stored up by Eumenes tinctor, wliich con- structs a nest of mud and attaches it to reeds, etc., not in a single, but a large mass, in which cells are excavated, similar to the nest of Chalicodoma micraria?* First, it uses its ovi- positor as a gimlet, and when its point has a little penetrated, then as a saw or rasp ; it likewise feels with its ovipositor, and. finding an unfinished or an empty cell it withdraws it immedi- atel}', without laying an egg." IcHNEUMOxiD.E Latrcille. The Ichneumon-flies arc readily recognized by the usually long and slender body, the long ex- serted ovipositor, which is often very long, and protected by a sheath formed of four stylets of the same length as the true ovipositor. The head is nonally rather square, with long, slender, many-jointed antenme which are not usually elbowed. The maxillary palpi are five to six-jointed, Avhile the labial * A query ( ?) after the name of a species indicates a doubt whether the insect really belongs to that species ; so with a ? after the name of a genus. A ? before both the genua and species expresses a doubt wliether that be the insect :it all. ICHNEUMO.MD.i;. I9f> palpi arc three to four-jointed. Tlic abdomen is inserted im- mediately over the hind pair of trochanters, and usually consists of seven visible segments. The fore-wings have one to three subcostal (cubital) cells. The larva is a soft, fleshy, cylindrical, footless grub, the rings of the body being moderately convex, and the head rather smaller than in the foregoing families. The eggs are laid by tlie parent either upon the outside or within the caterpillar, o." other larva, on which its 3'oung is to feed. When hatched it devours the fatty portions of its victim which dies gradually- of exhaustion. The ovipositor of some species is very long, and is fltted for boring through very dense substances ; thus Mr. Bond, of England, observes that BJij/ssa persuasoria actually bores through solid wood to deposit its eggs in the larvjB of Sirex ; the ovipositor is worked into the wood like an awl. When about to enter the pupa state the larva spins a cocoon, consisting in the larger species of an inner dense case, and a looser, thinner, outer covering, and escapes as a fl}^ through the skin of the caterpillar. The cocoons of the smaller gener.'i. such as Cryptus and Microgaster, may be found packed closely in considerable numbers, side by side, or sometimes placed u})- right within the body of caterpillars. The Ichneumon-flies are thus very serviceable to the agricul- turist, as they must annually destroy immense numbers of cat- erpillars. In Europe over 2,000 species of this family have been described, and it is probable that we have an equal num- ber of species in America ; Gerstaecker estimates that there are 4,000 to 5,000 known species. The Ichneumons also prey on certain Coleoptera and Ilymen- optcra, and even on larviis of PhryganicUv^ which live in the water. In Europe, Pimpla Fairmairii is })araf;itic on a spider. Clubione holosericea, according to Laboulbcne. Bolieman states that P. ovivora lives on a spider, and species of Pimpla and Ilemiteles were also found in a nest of spiders, according to Gravenhorst. Bouehe saj's that Pimpla rufata devours, during winter and spring, the eggs of Aranea diadema, and Ratzburg gives a list of fourteen species of Ichneumons parasitic on spiders, belonging to the genera Pimpla, Pezomachus, Ptero- rnalus, Cryptus. Ilemiteles, Microgaster, and Mesochorus. Mi-. 13 194 HYMENOPTEEA. Emerton informs me that he has reared a Pezomachus from the egg-sac of Attus, whose eggs it undoubtedly deA'ours. They are not even free from attaclcs of members of their own famil}'. as some smaller species are well known to prey on the larger. Being cut off from communication with the external world, the Ichneumon larva breathes by means of the two principal trachcEe, which terminate in the end of the body, and are placed, according to Ger- staecker, in com- munication Avith a stigma of its host. From the com- plete assimilation "^ of the liquid food. Fig- 123. the intestine ends in a cul de sac, as we have seen it in the larvse of Humble-bees and of Stylops, and as probably occurs in most other larva? of similar habits, such as young gall-flies, weevils, etc., which live in cells and do not eat solid food. The first subfamily, the Evamidce, are insects of singular and very diverse form, in which the antennae are either straight or elbowed, and thirteen to fourteen- jointcd ; the fore-wings have one to three subcostal (cubital) cells, and the hind Avings are almost without veins. In Evania and Foenus the abdomen has a very slender pedicel, originating next the base of the metanotum. The former genus has a remarkably short triangular compressed abdomen in the female, but ovate in the male. The ^'=- ^^i- species are parasitic on Blatta and allies. Evania Icevigaia Olivier (Fig. 123, $ and pupa) is a black species, and is para- sitic on the cockroach, Periplaneta, from the eggs of which we have taken the pupa and adult. The eggs of the cockroach are just large enough to accommodate a single Evania. This species ICHNEUMOXID^. I9t) is widely distributed, and in Cuba, according to Cresson, it devours the eggs of Periplaneta Americana. The genus Aidacodes of Cresson, " forms a very close con- necting-liuk between the minute Ichneumons and the Evanioo." A. nigriventris Cresson (Fig. 124, a; &, metathorax ; c, inser- tion of the abdomen) lives in Cuba. Fortius is quite a different genus, as the abdomen is very long and slender. Fcenus jaculator Linn, is known in Europe to frequent the nests of Crabronidce, ovipositing in the larvae. Pelecinus is a fa- miliar insect, the im- mensely elongated, linear abdomen of the female easily Fig. 125. distinguishing it. The male is extremelj' rare ; its abdomen is short and clavate. It strikingly resembles Trypoxyloiu though the abdomen is considerably larger. Pelecinus polv- cerator Drury (Fig. 125, $ and ?) is widely distributed throughout this country. The genuine Ichneumonidce have long, straight, multiarticu- late antenme. The first subcostal (cubital) cell of the fore- wings is united with the median cell lying next to it, while tho second is very small or Avholly wanting. There are two recurrent veins. Mr. Cresson has described /^ the genus Eiplwsoma (Fig. 12G), Fig. 126. which he states may be known by the long, slender, compressed abdomen, and the long posterior legs, with their femora toothed beneath the tips. E, annu- latum Cresson, a Cuban species, is, according to Poej", "para- sitic upon a larva of Pyralis." (Cresson.) In Ophion the antennae are as long as the bod}-, the abdo- men is compressed, and the species are honey-yellow in color. 0. macrurxtm Linn. (Fig. 127) attacks the American Silk- worm, Telea Polyphemus. Anomalon is a larger insect and usually black. A. vesparuni is, in Europe, parasitic on Vespa. 19G HYMENOPTERA. The genvis Bhyssa contains our largest species, and frequents the holes of boring insects in the trunks of trees, inserting its remai'kubl}' long ovipositor in the body of the larvae deeply embedded in the trunk of the tree. Harris states that Rhyssa (Pimpla) atrata and lunator (Fig. 128, male) of Fabricius, "may frequentl}^ be seen thrusting their slender borers, measur- ing from three to four in- ches in length, into the trunks of trees inhabited hy the grubs of the Tre- mex, and by other wood- ^'?- J"^"- eating insects ; and, like the feranle Tremex, they sometimes l)ecome fastened to the trees, and die without lieing a])le to draw their borers out again." The abdomen of the male is very slender. Pim2>la has the ovipositor half as long as the abdomen. P. pedalis Cresson is a parasite on t'lisioeampn. The genus Trorpis leads to Ichneumon. The antennas are sliortcr than the body ; the abdomen is slightly petiolate, fusi- form, and the second subcostal cell Is quadrangular. Tror/ns exesorius ]>rull6 is tawny red, and is a para- site of Papilio Asterias. The genus Iclineumon (Fig. 129) is one of great extent, probably containing over three hundred spe- cies. The abdomen is long and slender, lanceolate ovate, slightly petiolate. The second subcostal cell is five-sided, and the ovipositor is either concealed or slightly exserted. Fig. j2s. Ichneumon suturalis Say is a very common form, and has been reared in abundance from the larva of the Army-worm, Leu- cania unipuncta. The bod}- is pale rust-red, with l)lack sutures on the thorax. Another common species, also parasitic on the ICHXEUMONID^ . 197 Fig. 139. Army-worm, is the Ichneumon ^xiraiws, which is blackish, banded and spotted with yellow. The singular genus Grotea, established by Mr. Cresson, has along and narrow thorax (Fig. 130a), and a very long and petiolated abdomen (c). We have taken G. angidna Cresson, the only species known, from the cells of Crabro in raspberry stems received from Mr. 4.ugus. Cryptus is a genus of slender form, with a long, cylindrical abdo. men, which is petiolate. In the fe- jnale it is oval with an exserted ovipositor. Cresson figures a wdng (Fig. 131) of CJ ornatipennis, a Cuban species, which has the wings differently veined from the other species. Westwood remarks that in Europe a species of this genus preys on the; lai-vte of the Pt in idee, Pezomachus is usually wingless, and might at first sight read- ilj^ be mistaken for an ant. The body is small, the oval abdo- men petiolate, and the wings, when pres- ent, are very small. The species are very numerous. Gerstascker suggests that some may be wingless fema-les, belong- ing to winocd males of allied genera. The third subfamily is the Braconidm, containing those genera having long multiarticulatc antennie, and with the first subcostal cell separate from the first median, lying just behind it. The second subcostal cell is usually large, and there is only one recurrent vein. The genus Bracon is distinguished by the deeply excavated clypeus. The fu'st sub- costal cell is completely formed behind, Avauting the recurrent nerve ; the second cell is long, and four-sided. More than five hundred species, mostly of bright, gay colors, are already known. The genus Rhopcdosoma of Cres- son connects Bracon and other minute genera (Braconidae) with the true Ichneumons. li. Poeyi Cresson (Fig. 132) is a Fig. 131. Fisr. 1.30. 198 HTMENOPTERA. pale honey-yellow species, with a long club-shaped abdomeix It lives in Cuba. Rogas is a. genus differing from Bracon in having the three first abdominal rings long, forming a slender petiole. In Microgaster, a genus containing numerous species, the antennae are eighteen-jointed, and the abdomen is shorter than usual, and clavate. There are two or three subcostal cells, the second very small. Mi- crogaster nephojiterids (Plate 3, figs. 3, 3 a) is parasitic on Nephopter^^x Edmandsii, found in the cells of the Humble-bee. AjiJiidius, the parasite of the Plant-lice, is a most A^aluablo ally of man. It is known by its small size, and by having the second and third segments of the abdomen moving free on Fig. 132. each other. There are three cubital cells, thougli the wings are sometimes wanting. Aplddms (Praon) avena- pJds of Fitch, the Oat-louse Aphidius, is black with honey- yellow legs, and is one-tenth of an inch long. Aphidws (Toxares) triticcqiliis Fitch, the Wheat-louse Aphidius, is black, sliiniug, with thread-like antennse composed of twenty-fiv(! joints. Its length is .08 inch. Frequently the large size of the parasite causes the body of the dead Aphis to swell out into a globular form. Proctotrypid.e {Proctotrupii) Latreille. Egg-parasites. In this family are placed very minute species of parasitic Ich- neumon-like Ilymeuopters which have rather long and slender bodies, with straight or elbowed antennae of Aarious lengths, often haired on the joints, usually ten to fifteen, sometimes only eight in number, while the wings are covered with minute hairs and most of the nervures are absent. The maxillary palpi are three to six, the labial palpi usually three-jointed. The abdo- men has from five to seven joints, and the tarsi arc mostl}' five- jointed, rarely four-jointed. These insects are often so minute that they can scarcety be distinguished by the naked eye unless it is specially trained ; thej^ are black or brown, and very active in their habits. They may be swept off grass and herbage, from aquatic plants, or from hot sand-banks. They PROCTOTltYPID^i:. 19 'J prey on the wheat-flies bj^ inserting their eggs in their larvae, on gall-midges, and gall-flies, and on fungus-eating flies. In Europe, species of Teleas lay their eggs in those of other insects, especially butterflies and moths and hemipters, where they feed on the juices of the larvce growing within the egg, coming out as perfect Ichneumons. We probably have many species of these insects in this country. They usually occur in great numbers where the}' are found at all. They are almost too small to pin, and if transfixed would be unlit for study, and should, thereford, be gummed on mica, or put into small vials with alcohol. In Proctotrupes the antenna; are long, feathered, twelve- jointed. The fore-wings have the beginning of a cubital cell, and two longitudinal veins on the posterior half. The abdo- men is spindle-shaped and very acutely pointed, the terminal joints being tubular in their arrangement, and thus, as Westwood states, approaching the Chrysididce. An unknown species (Fig. 133) we haA'e taken at the Glen, in the White Mountains. /> The head of Diapria is horizontal and Fig. 133. longer than broad ; the ocelli are moved forward on to the front edge ; the long, filiform antennae have a projection on the under side, with the basal joint much elongated ; in the male they are thirteen or fourteen-jointed, with one joint less in the female. The wings are without stigma or veins. The abdomen is long, oval, pedicelled. In Europe, D. cecidomyi- arum Bouche is parasitic on the larvje of Cecidomyia arte- misitB. Esenbeck considers that this genus is also parasitic on the earth-inhabiting Tipiilidm. Gonatojms is a wingless genus, with the head very broad, transverse, and the front deeply hollowed out, while the ten- jointed antenni3e are long, slightly clavate, and the thorax is much elongated, deeply incised, forming two knot-like portions. Gonatopus lunatus Esenbeck, found in Europe, is one and a half lines long. Cemphron has the antenna; inserted near the mouth ; the}' are elbowed, and eleven-jointed in the male, and ten-jointed in the female. The abdomen has a very short pedicel. The fore- 20Q HYMENOPTERA. wings have a very short, bent costal (radial) vein. C. arma- tum Say was described from Indiana. The egg-parasite, Teleas, has the elbowed twelve-jointed an- tennae inserted very near the front of the head, and slightly hairy and simple in the male, but in the female terminated in a six-jointed club. The thorax is short, the legs thickened and adapted for leaping, and the abdomen is pedicelled. Many species have l)een found in Europe. According to Westwood, ''the type of this genus is the Ichneumon ovulorum of Linnaeus (Teleas Linnoii Esenbeck), Avhich Linnaeus and De Geer obtained from the eggs of moths." It has been raised from the eggs of several Bom- bi/cidce. " Bouche observed the female deposit Fig. 134. Jill Qgg in each of the eggs of a brood of Bom- byx neustria. He describes the larva as elliptical, white, shining, rugose, subincurved, and one-third of an inch long." (Westwood.) Of the extensive genus Platygaster over a hundred European species are already known. The body, especially the abdomen, is generally flattened, the antenna? are ten-jointed, and in the female clavate. The wing A-eins are absent ; the rather slender legs arc not adapted for leaping, and the tarsi are flve-jointed. A species of Platygaster (Fig. 134) not yet named, oviposits in the eggs of the Canker-worm moth, Anisopteryx vernata, and by its numbers does much to check the increase of this caterpillar. We have seen several of these minute insects engaged in inserting their eggs into those of the Canker- worm. Dr. Harris, in spealdng of the enemies of the IIessian-fl3-, states, that "two more parasites, which Mr. Herrick has not yet described, also destroy the Hessian-fly, while the latter is in the flax-seed or pupa state. Mr. Herrick says, that the egg- parasite of the Hessian-fly is a species of Platygaster, that it is very abundant in the autumn, when it lays its own eggs, four or five together, in a single egg of the Hessian-fly. This, it appears, does not prevent the latter from hatching, but the maggot of the Hessian-fly is unable to go through its trans- formations, and dies after taking on the flax-seed form. Mean- while its intestine foes are hatched, come to their growth, spin PROCTOTRYPID^. 201 themselves little brown cocoons within the skin of their victim, unci in due time, are changed to winged insects, and eat tlieir way out." P. error Pitch (Fig. 135) is closely allied to P. tipulce Kirby, which, in Europe, destroys great numbers of the Wheat-midge. Whether this, is a parasite of the midge, or not, Dr. Fitch has not yet determined. The habits of the genus Bethylus remind us of the fossorial wasps. Bethylus fascicornis, according to Ilaliday, "buries the larvaa of some species of Tinea, which feed upon the low tufts of Rosa spinosissima, dragging them to a considerable distance with great labor and solicitude, and employing, in the instance recorded by Mr. Haliday, the bore of a reed stuck in the ground instead of an arti- ficial funnel, for the cells which should contain the progeny of the Bethylus, with its store of provision." (AVestwood.) The genus Inostemma is re- markable for having the basal segment of the abdomen of the females furnished with a thick curved horn, which extends over the back of the thorax and head. Dr. Fitch states that /. inserens is supposed by Kirby to insert its eggs into those of the Wheat-midge. In the genus Galesus of Curtis, the mandibles are so enlarged and length- ened as to form a long beak, and Westwood fj\rther states that in some specimens the anterior wings have a notch at the ex- tremity. Say's genus Cojytera has similar wings. C. polita Say Avas discovered in Indiana. In the very minute species of Mymar and its allies, the head i« transverse, with the antennae inserted above the middle of the face ; they are long and slender and elbowed in the male, but clavate in the female. There are no palpi, while the very narrow wings have a very short subcostal vein and on the edges are provided with long dense cilioe. The antennje of Mymar are thirteen-jointed in the male, and nine-jointed in the female; the club is not jointed. The tarsi are four-jointed. and the abdomen is pedunculated. Mymar puIcheUns Curtis is a quarter of a line long. It is found in Europe. An allied 202 HYMENOPTERA. form Polynema ovulorum Linn, lays numerous eggs in a single butterfly's egg. In Anaphes the male antennte are twelve-jointed, those of the female nine-jointed, and the abdomen is subsessile and ovoid. In Anagrus the male antennoe are thirteen-jointed, those of the female nine-jointed, while the tarsi are four-jointed, and the acutely conical abdomen is sessile. No native species are known. The smallest Hymenopterous insect known, if not the most minute of all insects, is the Pteratomus Putnamii Pack, (Plate ;3, figs. 8, 8a, hind wing), which we first discovered on the body of an Anthophorabia in the minute eggs of which it is undoubtedly parasitic. It differs from Anagrus in the obtusely conical abdomen, and the narrower, very linear wings, which are edged with a fringe of long, curved hairs, giving them a graceful, feathery appearance. The fore-wings are fissured, a very interesting fact, since it shows the tendency of the wings of a low Hymenopterous insect to be fissured like those of Pterophorus and Alucita, the two lowest Lepidop- terous genera. It is one-ninetieth of an inch in length, CiiALCiDiD-T^: Westw^ood. This is a group of great extent ; the species are of small size ; they are often of shin}- colors, as the name of the principal genus implies, being either bronzen or metallic. They have also elbowed antennae with from six to fourteen joints, and the wings are often deficient in veins. In some genera, including Chalcis, the hind thighs are thickened for leaping. The difierences between the sexes, generally ver^' marked in Ilymenoptera, are here especially so. The abdo- men is usually seven-jointed in the male and six-jointed in the female, the other rings being aborted. The male of several species has the joints of the antenna swelled and furnished with long hairs above. Some of the species of Pteromalus are Aving- less, and closely resemble ants. They infest eggs and larA'se. Some species prey upon the Aphides, others lay their eggs in tjie nests of wasps and bees. One species is known in Europe to be a parasite of the common house-fly. Others consume the larvae of the Hessian-fly, and those Cecidomyiae that pro- duce galls, and also the true gall-flies (Cynips), Some are CHALCIDID^:. 203 parasites on other Ichneumon pai-asites, as there are species preying on the genus Aphidius, which is a parasite on the Aphis. Mr. "Walsh has bred a species of Hockeria and of Glyphe, which are parasitic on a Microgaster, which in turn preys upon the Army-worm, Leucania unipuncta ; and Chalcis albifrons Walsh, was bred from the cocoons of Pezomachus, an Ichneumon parasite of the same caterpillar. The pupae of some species are said to have the limbs and wings soldered together as in Lepidoptera, and the larvae sel- dom spin a silken compact cocoon. Wo have probably in this country at least a thousand species of these small parasites, nearly twelve hundred having been named and described in Europe alone. They are generally large enough to be pinned or stuck upon cards or mica ; some individuals should be preserved in this waj^, others, as wet specimens. Chalcis is known by the abdomen having a long pedicel, its much thickened, oval thighs, and curved tibite. Chalcis bra- cata (Fig. 136), so named by Mr. Sanborn "in allusion to the ornamental and trousered appearance of the posterior feet" is about .32 inch in length. "Rt-aumur has described and figured a species of Chalcis, which is parasitic in the nest of the American wasp Epipone nitidulans and which he regarded as the female of that wasp." (Westwood.) The genus Leucospis is of large size. It is known by having the large ovipositor laid upon the upper surface of the abdo- men, and being spotted and banded with yellow, resembling wasps. One of our more common species is the L. affinis (Fig. 137) of Say. The Cuban L. Poeyi Guerin is para- sitic on the Megachile Poeyi of Guerin. The well-known Joint- worm, Earytoma, (or Isosoma Walsh) produces galls on wheat- stems. The antennae are, in the male, slender and provided with verticils of hairs. The acutely oval abdomen has a short pedicel. The hind legs are scarcely thicker than the fore limbs. E. hordei Harris (Fig. 138) is found in gall-Uke swellings of wheat-stallts. It is still a matter of discussion, 204 HYMENOPTERA. whether it directly produces the galls, or is parasitic, like many of the family, on other gall-insects. Dr. Harris, who has studied the habits of the Joint-worm, states that the body of the adult fly is jet black, and that the thighs, shanks (tibiae), and claw-joints, are blackish, Avhile the knees and other joints of the feet, are pale-yellow. The females are .13 inch long, while the males are smaller, have a club-shaped abdomen, and the joints of the antennte surrounded with a verticil of hairs. The larva is described by Harris from specimens received from ^'irginia, as "sarying from one-tenth to nearly three-twentieths of an inch in length. It is of a pale j^ellowish white color, with an internal dusky streak, and is destitute of hairs. The head is round and partially retractile, with a distinct pair of jav>-s. and can be distinguished from the larvie of the dipterous; gall-flies by not having the v-shaped organs on the segment succeeding the head. During the sum- mer, according to Mr. Gourgas's observa- tions reported by Dr. Harris, and when the barley or wheat is about eight or ten inches high, the presence of the young Joint-worms is detected "by a sudden check in the growth of the plants, and the yellow color of their leaves," and several irregular gall- like swellings between the second and third joints, or, accord- ing to Dr. Fitch, "immediatel}' above the lower joint in tlio sheathing base of the leaf;" or, as Harris states, in the joint itself. The ravages of this insect have been noticed in wheat and barley. During November, in New England, the Avorms transform into the pupa state, according to the observations of Dr. A. Nichols, and "live through the winter nnchangcd in the straw, many of them in the stubble in the field, while others are carried away when the grain is harvested." In Virginia, however, the larva does not transform until late in February, or early in March, according to Mr. Glover. From early in Ma3% until the first week in July, the four-winged flies issue from the galls in the dry stubl)le, and are supposed to im- mediately la}^ their eggs in the stalks of the young wheat or barley plants. The losses by this insect has amounted, i]i Virginia, to over a third of the whole crop. The l)est remedy CHALCIDID^. 20;j against the attacks of this insidious foe, is to burn the stubble in tlie autumn or spring for several successive years. Plough- ing in the stubble does not injure the insects, as the}- can work their way out of the earth. It has been objected by Westwood, Ratzburg, and more recently by Mr. AValsh, (who afterwards changed his views), that as all the species of this family, so far as known, are para- sitic, the Eur3rtoma cannot be a gall-producer, and that the galls are made b}^ a dipterous insect (Cecidonijda) on v\liich the Eurytoma is a parasite ; but, as they offer no new facts to support this opinion, we are inclined to believe from the statements of Harris, Fitch, Cabell, T. Glover (Patent Office Report for 1854), and others, that the larva of the Eurytoma produces the gall. We nuist remember that the habits of comparatively few^ species of this immense family have been studied ; that the genus Eurytoma is not remotely allied to the Cynipidie, or true gall-ilies (which also comprise animal parasites), in which group it has actually been placed by Esen- l)eck, for the reason that in Europe "several species of Eurytoma have been observed to be attached to diiferent kinds of galls." (Westwood.) Dr. Fitch also describes the Yellow-legged Barley-fly, Eun/toma flawipes, which produces similar galls in barle}-, and differs from the Wheat Joint-vrorm in having yellow legs, while the antennae of the male are not surrounded with whorls of hair. The Eim;toma secaJis Fitch infests rye. It differs from E. hordci in "having the hind pair of shanks dull pale-yellow, as v>ell as the forw'ard ones." AVe shall also see beyond that several species of Saw-flies produce true galls, w'hile other species of the same genus are external feeders, which reconciles us more easily to the theory that the Eurytoma hordei, and the other species described by Dr. Filch, differ in their habits from others of the famil}"-, and are not ani- mal parasites. Indeed the Joint-worm is preyed upon by two Chalcid parasites, for Harris record3 finding the larvae, proba- bl}'^ of Torymus, feeding on the Eurytoma larvae, and that a species of Torymus (named T. Harrisii, by Dr. Fitch, and per- haps the adult of the first-named Torymus) and a species of Pteromalus are parasites on Eurytoma. In Monoclotitomems (Torymus) the third joiiit of the an- 20G HYMENOPTERA. tennae is minute, and the hind femora are thick, but not ser- rated, and beneath armed with a tooth near the tip. The wings are rudimentary so that it does not quit the cell. Newport states that the larva is flat, ver}^ hairy, and spins a silken cocoon when about to pupate. It is an "external feed- ing parasite" consuming the pupa as well as the larva of An- thophorabia. The imago appeal's about the last of June, perforating the cell of the bee. It also lives in the nests of Osmia, Anthophora, and Odynerus. The genus Anthopkorabia is so-called from being a parasite on Anthophora. The males differ remarkably from the females, especially in having simple instead of compound eyes, besides the usual three ocelli. A. megacliilis Pack. (Plate 3 ; fig. 7, larva ; 7 a, pupa) is a parasite on a species of Megachile. The larva is white, short and thick, cylindrical, with both extremities much alike ; the segments are slightly convex, and the terminal ring is orbicular and rather large. Length, .04 inch, being one-third as broad as long. On opening the cells of Megachile, we found nearly a dozen containing these para- sites, of which 150 larvae were counted clustering on the out- side of a dead and dry Megachile larva. In England they occur, according to Newport's observations, in much less num- bers, as he found from thirty to fifty in a cell of Anthophora. A few females hatched out in the middle of October, and there were a few pupaj left, but the majority wintered over in the larva state, and a new and larger brood appeared in the spring. Perilampus is a beautiful genus, with its shining, metallic tints. The eleven-jointed antennae are short, lying when at rest in a deep frontal furrow. The head is large, while the abdomen is slightly i^edicelled, being short, contracted, with the ovipositor concealed. P. platygaster Say and P. triavgu- laris Say were described from Indiana, The numerous species of Pteromolus often oviposit in the larvae of butterflies. In this genus the antennae are inserted in the middle of the front. The abdomen is nearly sessile, ob- tusely triangular, or acutely ovate in form, with the ovipositor concealed. The femora are slender. There are about three hundred species known to inhabit Europe. Pterom.alus va- nessoc Harris is a parasite on Vanessa Antiopa. P. disio- CHALCIDID^. 207 Vis. 130. campce Harris infests Clisiocampa. ^ ^ Pteromalus apum ia parasitic in the nests of the Mason-bee." (Westwood.) A spe- cies of this or an allied genus (Fig. 139) infests the eggs of the Clisiocampa Ameri- cana. Its eggs are probably laid within those of the Tent-caterpillar moth early in the summer, hatching out in the autumn, and late in the spring or early in June, An allied genus, Siphonura, is a para- site on galls. It resembles a beetle, Mor- della, from its very peculiar scutum. The antennae of Semiotellus are twelve-jointed. iS. (Ceraph- ron) destructor Say (Fig. 140), according to that author. destroj's the Hessian-fly, while lying in the "flax-seed" state. Fitch de- scribes it as being a tenth of an inch long, black, with a brassy green reflection on the head and thorax, while the legs and base of the abdomen are yellowish. In Encyrtvs, which comprises over a hundred species already known, usuall}- rather small in size, the body is short and rounded. The eleven-jointed antennas are inserted near the mouth. The thorax is square behind, and the sessile abdomen is short and broad at the base. Encyrtus Bolus and E. Reate are described from North America by Mr. F. Walker. Encyrtus varicornis is in Europe found as a parasite in the cells of Eumenes coarctata. The antennae of Eulophus are nine- jointed, with a long branch attached to the third, fourth, and fifth joints. The abdomen is flattened, sessile. E. basalls Say was described from Indiana. We figure a Chalcid (Fig. 141, <^), allied to Eulopus, which preys upon the American Tent Caterpillar. A species of Blastophaga (B. grossorum Grav.) is interest- ing as it is the means of assisting in the fertilization of the Fig Fig. 140. Fig. 141. 208 HYMEXOPTEEA. blossoms, which act, as applied to this instance of the fertiliza- tion of flowering plants by insects, has been called by Mr. Westwood " caprilication." Cynipidje Westwood. {Dijilolepariai Latreille.) Gall-flies. In this most interesting family we have a singular combination of zoological and biological characters. The gall-flies are closely allied to the parasitic Chalcids, but in their habits are plant- parasites, as they IIa'c in a gall or tumor formed by the ab- normal growth of the A'Cgetable cells, due to the irritation first excited when the egg is laid in the bark, or substance of the leaf, as the case may be. The generation of the summer broods is also anomalous, but the parthenogenesis that occurs in these forms, by which innneuse numbers of females arc produced, is necessary for the work they perform in the economy of nature. When we see a single oak hung with countless galls, the work of a single species, and learn how numerous are its natural enemies, it becomes evident that the demand for a great nu- merical increase muct be met by extraordinary means, like the generation of the summer broods of the Plant-lice. The gall-flies are readily recognized by tlieir resemblance to certain Chalcids, but the abdomen is much compres!-ed. and usually very short, while the second, or the second and third seg- ments, are greatly developed, the remaining ones being imbri- cated or covered one by the other, leaAing the hind edges exposed. Concealed within these, is the long, partially coiled, very slender ovipositor, which arises near the base of the abdo- men.* Among other distinguishing characters, are the straight *Fig. 142. I, iibdomen of Cynip.t quercus-aciculnfa Ostcn Sarken. Avith the ovii)os- itor exserted ; II, the same with the ovipositor retracted ; III, the abdcnioii of the female of Fif/ites (Diplolepis) it-lineatus Say; IV. the same showing: the ventral portion, in nature covered by the tergal portion of the abjnips quercus-futlUs^ O. Sacken, is strikingly like Aulax ? futilis, the parasite of its gall. The common gall on the black- berry stems produces two gall-flies which can hardly be told apart at first glance, although they belong to different genera." (Proceedings of the Entomological Society of Philadelphia.) Hartig has divided this family into tln-ee sections : First, Cynips and its allies, the true gall-flies (Psenides) in which the second (counting the slender pedicel as the first) segment of the abdomen is longer than half its length, and the subcostal area is narrow, the basal areolet (cell) being opposite the base of the former. Cynips confluens Harris forms the oak-apple commonly met with on the scrub-oak. There is a spring and summer brood. These galls, sometimes two inches in diameter, are gi'cen and pulpy at first, but when ripe have a hard shell Avith a spongy interior, in the centre of which, lodged in a woody kei-nel, which serves as a cocoon, the larva transforms, escaping through a hole, which it gnaws through both the kernel and shell. We have found the fl}- ready to escape in June, and Dr. Harris has found it in October. Two galls are represented on Plate 4, fig. 13 ; the larger of which has been tenanted, after the gall-flies had escaped, by an Odynerus. Cynips gallce-tinc- torke Olivier produces the galls of commerce, brought from Asia Minor. Biorhiza (Apophyllus Hartig) is a wingless genus, and lives beneath the earth in galls formed at the roots of oak trees. Biorhiza nigra Fitch is black throughout, including the antennae and feet, and is but .08 inch long. 212 IIYMEXOPTERA. Galls are often found on the 1)laekberrv, tenanted bj' another genus, DiastropliWi^ which has usually fifteen-jointed antenniv in the male, and one joint less in the female. On opening a gall containing this fl}^, we often find an inqniline gall-fly. Aulax, "showing the most striking resemblance in size, color- ing and sculpture, to the Diastrophus, their companion. The one is the ver^- counterpart of the other, hardly showing any differences, except the strictly generic characters." (Osten Saeken.) These galls are also infested by Chalcid parasites, Callimome (two species), Ormyrus, and Em-ytoma. Osten Saeken enumerates "■eight cynipidous galls on the dif- ferent kinds of roses of this country." The flies all belong to the genus Rhodites^ which is distinguished by the under side of the last abdominal segment being drawn out into a long point, while the antennas are fourteen-jointed in both sexes. B. rosce produces the bede- r/uar gall ("from the Hebrew hedeguach, said to mean rose-apple"). It was formerl}" used as a medicine. The galls form a moss-like mass, encircling the rose branch. Rhodites dichloceriis of Harris (Fig. 143), produces hard, woody, irregular swellings of the branches. We now come to the second section, the Guest gaU-Jlies (In- quilinre), Avhich are unable to produce galls themselves, as they do not secrete the gall-producing poison, though possessing a well developed ovipositor. Hence, like the Nomada, etc.. among bees, the}- are Cuckoo-flies, lading their eggs in galls already formed. This group may generally, according to Mr. Walsh, be dis- tinguished from the preceding b}' the sheaths of the ovipositor always projecting, more or less, bej'ond the "dorsal valve," which is a small, hairy tubercle at the top of the seventh ab- dominal segment. This dorsal valve also projects greatly. In almost all the species, the ovipositor projects from between the tips of the sheaths. Among the Inquiline genera are /Synophriis, AmbJynohis^ Synerges, and Aulax, which are guests of various species of C^niipides. In Figites and allies (Figitidas), the third section of the TENTHEEDINI D^ . 213 familj', the second segment is shorter than half the length of the abdomen, being much longer and less high and compressed than in the Cynipides, and the ovipositor is retracted within the abdomen. These insects are true internal parasites, re- sembling the Chalcids. Ihalia is a parasite on a wood-beetle^ This genus has, by Walsh, been placed in the Cynipides. Figites has feather-like antemiEe in the male ; it is a parasite on the larvfe of Sarcophaga. The genus AUotria is a para- site on Aphis. Walsh states that two genera, which ho has identified as Kleidotoma and Eucoila are true Figltidce, and "have the wings fringed like a Myrn,ar, and the former has them cmargi- nate at tip with the radial area in my species distinctly open, and the latter simple at tip with the radial area in my species marginally closed by a coarse brown vein." Eucoila is sup- posed to be parasitic on some insect attacking the turnip. Tenthredinid.e Leach. The Saw-flies connect the Ilymen- optera with the Lepidoptera. In the perfect state the}- con- form to the Hymenop- terous type, but as larvae they would often be mistaken for Lepi- dopterous larvte, and in their habits closel}' resemble many cater- pillars. The three di\isions of the body, usually so trenchantly marked in the liigher Ilymenoptera, are here ^'8- I'ti- less distinct, since the al)domen is sessile, its basal ring being broad and applied closely to the thorax, vvhile the succeeding rings are very equal in size. The head is broad and the thorax Avide, closely resembling that of the Lepidoptera. The wings (Fig. 144, fore-wing) are larger in proportion to the rest of the body than usual ; they are more net- veined, the cells being more numerous and extending to the outer margin.* *In treating of this family v,e avail ourselves largely of the important work on the American species, puljlishing at the time of writing, by Mr. E. N'orton, in the Transactions of the American Entomological Societv, vols. 1, 2. Wc therefore 214 HYMENOPTERA. All these ctiaracters show that the saw-fl3' is, d degi'adecl Ilymenopter. The autennse are not elbowed ; are rather short and simple, clavate, but in rare instances fissured or feathered. The ab- tlomen consists, usually, of eight external segments, the two last being aborted on the under side, owing to the great develop- ment of the ovipositor. The ovipositor or "saw" (compare Fig. 24) consists of two lamella?, the lower edge of which is toothed and fits in a groove in the under side of the upper one, which is toothed above, both protected by the usual sheath-like stylets. On pressing, saj^s Lacaze-Duthiers, the end of the abdomen, we see the saw depressed, leave the direction of the axis of the body, and become perpendicular. By this movement the saw, which both cuts and pierces, makes a gash in the soft part of the leaf Avherc it deposits its eggs. The eggs are laid more commonly near the ribs of the leaf, in a series of slits, each slit containing but a single egg. '•Some species, on the other hand, introduce their eggs by means of their saws into the edges of leaves {JSfematus conjn- gatiis Dahlb.), and others beneath the longitudinal ribs of the leaves. A few, indeed, merely fasten their eggs upon the outer sux'face of the leaves (Nematusgrosstdaria', etc.), attaching them together like a string of beads (Reaumur, vol. v, plate 10, fig. 8), whilst a few place them in a mass on the surface of the leaf (ibid, plate 11, figs. 8, 9)." (Westwood.) The irritation set up by the saws in the wounded leaf, causes a flow of sap which is stated by Westwood to be imbibed by the egg, so that it swells gradually to twice its original size. It is known that the eggs of ants increase in size as the embryo develops, and we would copy his diagram (Fig. 144), showing the venation of the wing (compare Fig. 29 and our nomenclature), with the explanation of i)arts given by him. a, stigma; b, costa or costal margin; c, apical margin; coidal vein; 71, flrst and second inner api- cal or submarginal nervures. Bulla.' or clear spots, on the veins or nervures, with bullar or clear lines crossing them. 1,2, marginal or radial cells ; S, 4, 5, 0, submar- ginal or cubital cells ; 7, 8, 9, discoidal cells ; 10, costal cell ; 11, 12, brachial or me- dial cells; 13, 14, inner and outer apical cells. (Hinder cell*, Hartig. Cellule du limbe, St. Farg.) No. 11 is sometimes the medial, and Xos. 12 and 13 the submcdial colls; Nos. 9 and 14 the apical cells; Nos. 7 and 13 discoidal; Nos. 10, 11, 12, l'>, the lirst, second, third and fourth brachial cells; I."), lanceolate cell. 1, open; 2, con- tracted ; 3, petiolate; 4, subcontracted; 5, with oblique cros's uervure; G, with straight cross nervurc. TEXTHIIEDIXIDyE. 21') question whether the increase in size of the eggs of the Saw- ^y is not rather clue to the same cause. The punctures in the plant often lead, in some genera, to the production of galls, in which the larvai live, thus showing the near relationship of this famil}' to the gall-flies (Cynipidse). The larvoe strongly resemble caterpillars, but there are six to eight pairs of abdominal legs, whereas the caterpillar has but five pairs. Many species curl the hind body up spirally when feeding or at rest. They are usuallj^ green, with lines and markings of various colors. They usually moult foui- times, the last change being the most marked. Most of the larvoe secrete silk and spin a tough cocoon, in which they hiber- nate in the larva, and often in the pupa state. The pupa has free limbs, as in the other families. The eggs are usually de- posited in the leaves of plants, but in a few cases, according to Norton, in slender or hollow stems. While some are slug- shaped, like the Pear-slug, others like Lyda inanita, mentioned bj' Westwood, live on rose bushes, and construct a "portable case, formed of bits of rose-leaves arranged in a spiral coil ; " and other species are leaf-rollers, like the Tortricids. The larva of Cephus does injury to grain, in Europe, by boring within the stems of wheat. A remarkable instance of the care of the saw-fly for her young, is recorded by Mr. R. II. Lewis, who observed in Australia, the female of Perga Letcisii deposit its eggs in a slit next the midribs of an Eucalyptus leaf. They were placed transversely in a double series. "On this leaf the mother sits till the exclusion of the larvjc ; and as soon as these ai-e hatched, the parent follows them, sitting with out- stretched legs over her brood, protecting them from the attacks of parasites and other enemies with admirable perseverance.'* (Westwood.) The species are mostly limited to the temperate zone, but few being found in the tropics. The perfect insects mostly occur in the early summer, and are found on the leaves of the trees they infest, or feeding on flowers, especially those of the umbellifei-ous plants. The genus Cimbex contains our largest species, the antennae ending in a knob. (7. Americana Leach is widel}' distributed, and varies greatly in color. The large whitish larva, with a 216 HYMENOPTERA. blackish dorsal stripe, may be found rolled up in a spiral on the leaves of the elm, birch, linden and willow trees. When disturbed it ejects a fluid from pores situated above the spira- cles. It constructs a large tough parchment-like cocoon, and the fly appears in the early summer. The genus Trichiosoma is recognized by its hairy bod}^, and the antennae have five joints preceding the three-jointed club. T. triavgulum Kirby is found in British America and Colorado, and a variety, T. bicolor Harris, on Mount Wasliington ; it is black, except the tij) of the al^domen, with the fourth and fifth joints of the autennie piceous, and the thorax is covered with ash-colored hair. In Abia the antennre are seven-jointed, with the club obtuse ; the bod}^ is villose, the abdomen having a metallic silken hue. The Abia ccqynfolii Norton (Fig. 145, larva) is very destruc- tive to the Tartarian Honeysuckle, sometimes stripping the bush of its leaves during successive sea- sons in Maine and Massachusetts. It hatches out and begins its ravages very soon after the leaves are out, eating cir- cular holes in them. It lies curled up on the leaf and when disturbed emits drops of a watery fiuid from the pores in the sides of the body, and then falls to the ground. During the early part of August it spins a pale yellowish silken cocoon, but does not change to a pupa, Mr. Rile}' states, until the following spring. He describes the larva as being common about Chicago ; that it is "bluish green on the back, and yellow on the sides, which are pale near the spiracles, and covered with small l)lack dots. Between every segment is a small, transverse, yellow band, with a black spot in the middle and at each end. Head free, of a brownish black above and color of the body beneath." The fly is described by Norton as being black, with faint greenish reflections on the abdomen ; there are two white bands at the base of the metathorax, and the wings are banded. It is .36 inch long and the wings ex- pand .70 inch. The larvae can easity be destroyed from their Fig. 145. TENTHREDINIDiE. 217 habit of fulling to the ground when the bnsh is shaken, where they can be crushed by the foot. Dr. Fitch has reared Abia cerasi from one or two cocoons found on the wild cherr}^, the fly appearing in New York during March. Hylotoma is a much smaller genus ; the basal joint of the antenna is oval, while the second is small and round, and the terminal joint is very long. The larva is twenty-footed, and when eating curves the end of the body into the form of an S. The pupa is protected by a gauzy, doubly enveloping cocoon. H. McLeayi Leach is wholly black, sometimes with a tinge of blue. It is found throughout the Northern States. The genus Pristiphora, closely allied to Nematus, is known by its nine-jointed antenmB, and the single costal cell ; the first submarginal (subcostal) cell having two recurrent veinlets. P. identidem Norton has been discovered b}' Mr. W. C. Fish to be destructive to the cranberry on Cape Cod. He has reared the insect, and sent me the following notes on its habits, while the adult fly has been identified by Mr. Norton, to whom I submitted specimens. The larvse were detected in the first week of June, eating the leaves ; "they were light or pale yel- lowish green when first hatched," and grew darker with age. The head of the young was dark, but in the full-grown worm lighter. When full-grown they were about .30 of an inch in length, and had two lighter whitish green stripes running along the back from head to tail. They had spun their cocoons by the 20th of June in the rubbish at the bottom of the rearing bot- tles. On the 29th of June the}^ came out in the perfect state. We would add to this description that the body, in two alco- holic specimens of the larvffijwas long, cylindrical, and smooth, with seven pairs of abdominal feet. The head is full, rounded and blackish, but after the last moult pale honey-yellow. The male is shining black, and Mr. Norton informs me that it is his P. idiota. P. gmssularke AYalsh is a widely difinsed species in the Northern and Western States, and injures the currant and gooseberry. The female fly is shining black, while the head is dull yellow, and the legs are honey-yellow, with the tips of the six tarsi, and sometimes the extreme tips of the hinder tibiae and of the tarsal joints pale dusky for a quarter of their length. The wings are partiall}^ hyaline, with black veins, a 218 HYMENOPTERA. honej'-j'ellow costa, and a dusky stigma, edged with honey- yellow. The male ditters a little in having black eoxtie. Mr. Walsh states that the larA-a is a pale grass-green worm, half an inch long, with a black head, which becomes green after the last moult, but with a lateral brown stripe meeting with the opposite one on the top of the head, where it is more or less confluent ; and a central brown-black spot on its face. It appears the last of June and earl}' in July, and a second brood in August. They spin their cocoons on the bushes on wliich they feed, and the fl}- appears in two or three weeks, the sixBcimens reared by him flying on the 26th of August. P. sycoplmnta Walsh is an "inquiline," or guest gall-saw-fly, inhabiting a Cecidomyian gall on a willow. The genus Euura comprises scA^eral gall-making species. It differs from the preceding genus in the second, instead of the first, submarginal cell having two recurrent venules. Mr. Walsh has raised E. orbitalis Norton (E. genuiua Walsh) from galls found on Salix humilis. This gall is a bud wliich is found enlarged two or three times its natural size, before it unfolds in spring. The larva is twenty-footed, is from .13 to .19 of an inch long, of a greenish white color, and the head is dusky. It bores out of its gall in autumn, descending an inch into the ground, where it spins a thin, silken, whitish cocoon. The gall of E. saUcis-ovnm Walsh is found on Salix cordata. The female is shining yellow, while the ground color of the male is greenish white. The gall of this species is an oval roundish, sessile, one-chambered, gi-een or broAvnish swell- ing, .30 to .50 of an inch long, placed lengthwise on the side of small twigs. The larva is pale yellowish, and the fly appears in April. The fly is, according to Walsh, " absolutely iindistin- guishable by any reliable character from the guest gall-saw-fly, Euura perturhans Walsh," which inhabits dipterous galls made by Cecidomyian flies on the Avillow and grape (Walsh) . If these two ''species" do not differ from each other, either in the larva or adult state, "by any reliable characters," then one must ([uestion whether the variation in habits is sufficient to separate them as species, and whether E. salicis-ovimi does not, some- times, instead of forming a new gall, lay its eggs in a gall ready- made by a dipterous gall-fl3^ We have seen that Od^'nerus TEXTIIUEDIXID.E. 219 albophaleratus, which usually makes a luud cell situated in the most diverse places, in one case at least, makes no cell at all, but uses the tunnel bored out by a Ceratina ! and yet we should not split this species into two, on account of this difference in its habits. We had written this before meeting with Mr. Norton's remark that "it is difficult to give a hearty assent to Mr. Walsh's inquilines or guest-flies, without further inves- tigation." (Transactions of the American Entomological Society, vol. i, p. 194.) In Nematus the nine-jointed antennae have the third joint longest. There is one costal and four subcostal cells, the second cell receiving two recurrent veinlets ; the basal half of the lanceolate cell is closed ; the hind wings have two mid- dle cells, and the tibige are simple. The larvae are hairy with warts behind the abdominal feet. The}- have twenty feet, the fourth and eleventh segments (count- ing the head as one) being footless. They are either solitary, feeding upon the leaves of plants, or social and generally found on pine trees, while some species live in the galls of plants. The pupa, according to Hartig, is enclosed in an egg-shaped cocoon, like that of Lophyrus, but less firm, though with more outside silk. It is generally made in the earth, or in leaves which fall to the ground. N. vertebratus Say is green, with the antennae and dorsal spots blackish, the thorax being trilineate. There are fifty species in this country, of which the most injurious one, the Gooseberry saw-fly, has been brought from Europe. This is the JSf. ventricosus Klug Avhich was undoubtedly imported into this country about the year 18G0, spreading mostly from Rochester, N. Y., where there are extensive nurseries. It does more injury to the currant and gooseberry than any other native insect, except the currant moth (Abraxas ribearia). Professor Winchell, who has studied this insect in Ann Arbor, Michigan, where it has been very destructive, observed the female on the 16th of June, while depositing her cylindrical, whitish and transparent eggs, in regular rows along the under side of the veins of the leaves, at the rate of about one in fort^^-five seconds. The embrj'o escapes from the egg in four days. It feeds, moults and burrows into the gi'ound within a period of eight days. It remains thirteen da3'S in the ground, being 220 HYMENOPTEEA. most of the time in the pupa state, while the % lives nine daj-s. The first brood of worms appeared May 21, the second brood June 25, Winehell describes the larva as being pale-green, Avith the head, tail and feet, black, with numerous black spots regularly arranged around the body, from which arise two or more hairs. Figure 14(j, 1 , shows the eggs deposited along the under side of the midribs of the leaf; 2, the holes bored by the very young larvae, and 3, those eaten b}^ the larger worms. In transporting gooseberry and currant bushes, Walsh recom- mends tliat the roots be carefully cleansed of dirt, so that the cocoons may not be car- ried about from one gar- den to another. The leaves of the bushes should be examined during the last Aveek of Ma^^ , and as only ^ a few leaves are affected at first, these can be de- tected by the presence of the eggs and the little round holes in them, and should be plucked off and burnt. The female saw- fly is bright honey-yelloAV. with the head black, but yellow beloAv the insertion of the antennre. The male differs in its black thorax, and tlic antciniaj are paler reddish than in the female.* The genus EmjjJif/tus has nine-jointed antennfB ; the third * Mr. Norton has communicated the followhig description of the larva of anothnr ea^ir-fly of this genus which infests the weeping-willow. " Xeiii'.ttus trUineatus Norton. The larva; of this w^re flrst seen upon the weep- ing-willows al)Out August 1st, in immense numbers, almost wholly stripping large trees of their leaves. They begin upon the edge of tlie leaf and eat all of it except the inner midrib. They are very sensitive to disturbances, very lively, and arc generally found with the hinder part of tiieir Ijodies bent up over the back. They are twenty-footed, of a bright green color, palest at head and tail, with live rows of black dots down the back, the outer row upon each side irregular and with inter- vals. Ou each side above the feet is another row of larger black dots, and the three anterior pair of feet are black at the base, middle and tip. " A great number of the saw-flies were foimd flying about the tr