Chapter VIII: Hemiptera, or Bugs—anoplura 532 (1)

NOTES AND CORRIGENDA TO VOLUME VI. AND TO INSECTA OF VOLUME V. 602

INDEX 603

{vii}SCHEME OF THE CLASSIFICATION ADOPTED IN THIS BOOK

Order. Sub-order, Family. Sub-Family Group.
Division, or Tribe.
or Series.

HYMENOPTERA (_continued from Vol. V_).
PETIOLATA. (_continued from Vol. V_).
TUBULIFERA (p. 1)
CHRYSIDIDAE (p. 1).
ACULEATA (p. 4)
_ANTHOPHILA_ (p. 10)
APIDAE (p. 10)
Archiapides (p. 21).
Obtusilingues (p. 22).
Andrenides (p. 23).
Denudatae (p. 29).
Scopulipedes (p. 32).
Dasygastres (p. 35).
Sociales (p. 53).
_DIPLOPTERA_ (p. 71)
EUMENIDAE (p. 72).
VESPIDAE (p. 78).
MASARIDAE (p. 88).
_FOSSORES_ (p. 90)
SCOLIIDAE (p. 94)
Mutillides (p. 94).
Thynnides (p. 96).
Scoliides (p. 97).
Sapygides (p. 99).
Rhopalosomides (p. 100).
POMPILIDAE (p. 101).
SPHEGIDAE (p. 107)
Sphegides (p. 107).
Ampulicides (p. 114).
Larrides (p. 116).
Trypoxylonides (p. 118).
Astatides (p. 119).
Bembecides (p. 119).
Nyssonides (p. 123).
Philanthides (p. 124).
Mimesides (p. 127).
Crabronides (p. 128).
_HETEROGYNA_ (p. 131)
FORMICIDAE (p. 131)
Camponotides (p. 144).
Dolichoderides (p. 157).
Myrmicides (p. 158)
Myrmicini (p. 159).
Attini (p. 165).
Pseudomyrmini (p. 168).
Cryptocerini (p. 169).
Ponerides (p. 170).
Dorylides (p. 174)
Ecitonini (p. 175).
Dorylini (p. 177).
Amblyoponides (p. 180).

Order. Sub-Order, Family. Sub-Family or
Division, Tribe.
or Series.

COLEOPTERA (p. 184)
LAMELLICORNIA (p. 190)
PASSALIDAE (p. 192).
LUCANIDAE (p. 193).
SCARABAEIDAE (p. 194)
Coprides (p. 195).
Melolonthides (p. 198).
Rutelides (p. 198).
Dynastides (p. 199).
Cetoniides (p. 199).
ADEPHAGA OR CARABOIDEA (p. 200)
CICINDELIDAE (p. 201).
CARABIDAE (p. 204)
Carabides (p. 206).
Harpalides (p. 206).
Pseudomorphides (p. 206).
Mormolycides (p. 206).
AMPHIZOIDAE (p. 207).
PELOBIIDAE (p. 207).
HALIPLIDAE (p. 209).
DYTISCIDAE (p. 210).
POLYMORPHA (p. 213)
PAUSSIDAE (p. 213).
GYRINIDAE (p. 215).
HYDROPHILIDAE (p. 216).
PLATYPSYLLIDAE (p. 219).
LEPTINIDAE (p. 220).
SILPHIDAE (p. 221).
SCYDMAENIDAE (p. 223).
GNOSTIDAE (p. 223).
PSELAPHIDAE (p. 223).
STAPHYLINIDAE (p. 224).
SPHAERIIDAE (p. 227).
TRICHOPTERYGIDAE (p. 227).
HYDROSCAPHIDAE (p. 228).
CORYLOPHIDAE (p. 228).
SCAPHIDIIDAE (p. 229).
SYNTELIIDAE (p. 229).
HISTERIDAE (p. 230).
PHALACRIDAE (p. 231).
NITIDULIDAE (p. 231).
TROGOSITIDAE (p. 232).
COLYDIIDAE (p. 233).
RHYSODIDAE (p. 234).
CUCUJIDAE (p. 234).
CRYPTOPHAGIDAE (p. 235).
HELOTIDAE (p. 235).
THORICTIDAE (p. 236).
EROTYLIDAE (p. 236).
MYCETOPHAGIDAE (p. 237).
COCCINELLIDAE (p. 237).
ENDOMYCHIDAE (p. 239).
MYCETAEIDAE (p. 239).
LATRIDIIDAE (p. 240).
ADIMERIDAE (p. 240).
DERMESTIDAE (p. 241).
BYRRHIDAE (p. 242).
CYATHOCERIDAE (p. 243).
GEORYSSIDAE (p. 243).
HETEROCERIDAE (p. 243).
PARNIDAE (p. 243).
DERODONTIDAE (p. 244).
CIOIDAE (p. 245).
SPHINDIDAE (p. 245).
BOSTRICHIDAE (p. 246).
PTINIDAE (p. 246)
Ptinides (p. 246).
Anobiides (p. 246).
MALACODERMIDAE (p. 248)
Lycides (p. 248).
Drilides (p. 248).
Lampyrides (p. 248).
Telephorides (p. 248).
MELYRIDAE (p. 252).
CLERIDAE (p. 253).
LYMEXYLONIDAE (p. 254).
DASCILLIDAE (p. 255).
RHIPICERIDAE (p. 256).
ELATERIDAE (p. 256)
Throscides (p. 260).
Eucnemides (p. 260).
Elaterides (p. 260).
Cebrionides (p. 260).
Perothopides (p. 260).
Cerophytides (p. 260).
BUPRESTIDAE (p. 261).
HETEROMERA (p. 262)
TENEBRIONIDAE (p. 263).
CISTELIDAE (p. 264).
LAGRIIDAE (p. 264).
OTHNIIDAE (p. 265).
AEGIALITIDAE (p. 265).
MONOMMIDAE (p. 265).
NILIONIDAE (p. 265).
MELANDRYIDAE (p. 265).
PYTHIDAE (p. 265).
PYROCHROIDAE (p. 266).
ANTHICIDAE (p. 266).
OEDEMERIDAE (p. 266).
MORDELLIDAE (p. 267).
CANTHARIDAE (p. 269).
TRICTENOTOMIDAE (p. 275).
PHYTOPHAGA (p. 276)
BRUCHIDAE (p. 276)
CHRYSOMELIDAE (p. 278)
Eupoda (p. 280).
Camptosomes (p. 281).
Cyclica (p. 282).
Cryptostomes (p. 282).
CERAMBYCIDAE (p. 285)
Prionides (p. 287).
Cerambycides (p. 287).
Lamiides (p. 287).
RHYNCHOPHORA (p. 288)
ANTHRIBIDAE (p. 290).
CURCULIONIDAE (p. 290).
SCOLYTIDAE (p. 294).
BRENTHIDAE (p. 295).
AGLYCYDERIDAE (p. 297).
PROTORHINIDAE (p. 298).
STREPSIPTERA (p. 298)
STYLOPIDAE (p. 298).

LEPIDOPTERA (p. 304)
RHOPALOCERA (p. 341)
NYMPHALIDAE (p. 343)
Danaides (p. 344).
Ithomiides (p. 346).
Satyrides (p. 347).
Morphides (p. 348).
Brassolides (p. 349).
Acraeides (p. 350).
Heliconiides (p. 351).
Nymphalides (p. 352).
ERYCINIDAE (p. 354)
Erycinides (p. 355).
Libytheides (p. 355).
LYCAENIDAE (p. 356).
PIERIDAE (p. 357).
PAPILIONIDAE (p. 359).
HESPERIIDAE (p. 363).
HETEROCERA (p. 366)
CASTNIIDAE (p. 371).
NEOCASTNIIDAE (p. 372).
SATURNIIDAE (p. 372).
BRAHMAEIDAE (p. 374).
CERATOCAMPIDAE (p. 375).
BOMBYCIDAE (p. 375).
EUPTEROTIDAE (p. 376).
PEROPHORIDAE (p. 377).
SPHINGIDAE (p. 380).
COCYTIIDAE (p. 382).
NOTODONTIDAE (p. 383).
CYMATOPHORIDAE (p. 386).
SESIIDAE (p. 386).
TINAEGERIIDAE (p. 387).
SYNTOMIDAE (p. 388).
ZYGAENIDAE (p. 390).
HIMANTOPTERIDAE (p. 392).
HETEROGYNIDAE (p. 392).
PSYCHIDAE (p. 392).
COSSIDAE (p. 395).
ARBELIDAE (p. 396).
CHRYSOPOLOMIDAE (p. 396).
HEPIALIDAE (p. 396).
CALLIDULIDAE (p. 400).
DREPANIDAE (p. 400).
LIMACODIDAE (p. 401).
MEGALOPYOGIDAE (p. 404).
THYRIDIDAE (p. 404).
LASIOCAMPIDAE (p. 405).
ENDROMIDAE (p. 406).
PTEROTHYSANIDAE (p. 406).
LYMANTRIIDAE (p. 406).
HYPSIDAE (p. 408).
ARCTIIDAE (p. 408).
AGARISTIDAE (p. 410).
GEOMETRIDAE (p. 411).
NOCTUIDAE (p. 414).
EPICOPEIIDAE (p. 418).
URANIIDAE (p. 419).
EPIPLEMIDAE (p. 420).
PYRALIDAE (p. 420).
PTEROPHORIDAE (p. 426).
ALUCITIDAE (p. 426).
TORTRICIDAE (p. 427).
TINEIDAE (p. 428).
ERIOCEPHALIDAE (p. 433).
MICROPTERYGIDAE (p. 435).

DIPTERA (p. 438)
ORTHORRHAPHA NEMOCERA (p. 455)
CECIDOMYIIDAE (p. 458).
MYCETOPHILIDAE (p. 462).
BLEPHAROCERIDAE (p. 464).
CULICIDAE (p. 466).
CHIRONOMIDAE (p. 468).
ORPHNEPHILIDAE (p. 470).
PSYCHODIDAE (p. 470).
DIXIDAE (p. 471).
TIPULIDAE (p. 471)
Ptychopterinae (p. 472).
Limnobiinae (p. 473).
Tipulinae (p. 475).
BIBIONIDAE (p. 475).
SIMULIIDAE (p. 477).
RHYPHIDAE (p. 478).
ORTHORRHAPHA BRACHYCERA (pp. 455, 478)
STRATIOMYIDAE (p. 478).
LEPTIDAE (p. 479).
TABANIDAE (p. 481).
ACANTHOMERIDAE (p. 483).
THEREVIDAE (p. 484).
SCENOPINIDAE (p. 484).
NEMESTRINIDAE (p. 484).
BOMBYLIIDAE (p. 485).
ACROCERIDAE (p. 489).
LONCHOPTERIDAE (p. 490).
MYDAIDAE (p. 491).
ASILIDAE (p. 491).
APIOCERIDAE (p. 492).
EMPIDAE (p. 492).
DOLICHOPIDAE (p. 493).
CYCLORRHAPHA ASCIZA (pp. 455, 494)
PHORIDAE (p. 494).
PLATYPEZIDAE (p. 496).
PIPUNCULIDAE (p. 496).
CONOPIDAE (p. 497).
SYRPHIDAE (p. 498).
CYCLORRHAPHA SCHIZOPHORA (pp. 456, 503)
MUSCIDAE ACALYPTRATAE (p. 503).
ANTHOMYIIDAE (p. 506).
TACHINIDAE (p. 507).
DEXIIDAE (p. 510).
SARCOPHAGIDAE (p. 510).
MUSCIDAE (p. 511).
OESTRIDAE (p. 514).
PUPIPARA (pp. 456, 517)
HIPPOBOSCIDAE (p. 518).
BRAULIDAE (p. 520).
STREBLIDAE (p. 521).
NYCTERIBIIDAE (p. 521).

APHANIPTERA (pp. 456, 522)
PULICIDAE (p. 522).

THYSANOPTERA (p. 526)
TEREBRANTIA (p. 531).
TUBULIFERA (p. 531).

Order. Sub-Order. Series. Family.

HEMIPTERA (p. 532)
HETEROPTERA (pp. 543, 544)
GYMNOCERATA (p. 544)
PENTATOMIDAE (p. 545).
COREIDAE (p. 546).
BERYTIDAE (p. 548).
LYGAEIDAE (p. 548).
PYRRHOCORIDAE (p. 549).
TINGIDAE (p. 549).
ARADIDAE (p. 550).
HEBRIDAE (p. 551).
HYDROMETRIDAE (p. 551).
HENICOCEPHALIDAE (p. 554).
PHYMATIDAE (p. 554).
REDUVIIDAE (p. 555).
AËPOPHILIDAE (p. 559).
CERATOCOMBIDAE (p. 559).
CIMICIDAE (p. 559).
ANTHOCORIDAE (p. 560).
POLYCTENIDAE (p. 560).
CAPSIDAE (p. 561).
SALDIDAE (p. 562).
CRYPTOCERATA (p. 562)
GALGULIDAE (p. 562).
NEPIDAE (p. 563).
NAUCORIDAE (p. 565).
BELOSTOMIDAE (p. 565).
NOTONECTIDAE (p. 567).
CORIXIDAE (p. 567).
HOMOPTERA (pp. 543, 568)
TRIMERA (p. 544)
CICADIDAE (p. 568).
FULGORIDAE (p. 574).
MEMBRACIDAE (p. 576).
CERCOPIDAE (p. 577).
JASSIDAE (p. 578).
DIMERA (p. 544)
PSYLLIDAE (p. 578).
APHIDAE (p. 581).
ALEURODIDAE (p. 591).
MONOMERA (p. 544)
COCCIDAE (p. 592).
ANOPLURA (p. 599)
PEDICULIDAE (p. 599).

{1}CHAPTER I

HYMENOPTERA PETIOLATA _CONTINUED_

SERIES 2. TUBULIFERA OR CHRYSIDIDAE—SERIES 3. ACULEATA—GENERAL— CLASSIFICATION—DIVISION I. ANTHOPHILA OR BEES

The First Series—Parasitica—of the Sub-Order Hymenoptera Petiolata was discussed in the previous volume. We now pass to the Second Series.

SERIES 2. HYMENOPTERA TUBULIFERA.

_Trochanters undivided; the hind-body consisting of from three to five
visible segments; the female with an ovipositor, usually retracted,
transversely segmented, enveloping a fine, pointed style. The larvae
usually live in the cells of other Hymenoptera._

The Tubulifera form but a small group in comparison with Parasitica and Aculeata, the other two Series of the Sub-Order. Though of parasitic habits, they do not appear to be closely allied to any of the families of Hymenoptera Parasitica, though M. du Buysson suggests that they have some affinity with Proctotrypidae; their morphology and classification have been, however, but little discussed, and have not been the subject of any profound investigation. At present it is only necessary to recognise one family, viz. Chrysididae or Ruby-wasps.[1] These Insects are usually of glowing, metallic colours, with a very hard, coarsely-sculptured integument. Their antennae are abruptly elbowed, the joints not being numerous, usually about thirteen, and frequently so {2}connected that it is not easy to count them. The abdomen is, in the great majority, of very peculiar construction, and allows the Insect to curl it completely under the anterior parts, so as to roll up into a little ball; the dorsal plates are very strongly arched, and seen from beneath form a free edge, while the ventral plates are of less hard consistence, and are connected with the dorsal plates at some distance from the free edge, so that the abdomen appears concave beneath. In the anomalous genus _Cleptes_ the abdomen is, however, similar in form to that of the Aculeate Hymenoptera, and has four or five visible segments, instead of the three or four that are all that can be seen in the normal Chrysididae. The larvae of the Ruby-flies have the same number of segments as other Hymenoptera Petiolata. The difference in this respect of the perfect Chrysididae from other Petiolata is due to a greater number of the terminal segments being indrawn so as to form the tube, or telescope-like structure from which the series obtains its name. This tube is shown partially extruded in Fig. 1; when fully thrust out it is seen to be segmented, and three or four segments may be distinguished. The ovipositor proper is concealed within this tube; it appears to be of the nature of an imperfect sting; there being a very sharply pointed style, and a pair of enveloping sheaths; the style really consists of a trough-like plate and two fine rods or spiculae. There are no poison glands, except in _Cleptes_, which form appears to come very near to the Aculeate series. Some of the Chrysididae on occasions use the ovipositor as a sting, though it is only capable of inflicting a very minute and almost innocuous wound.

Although none of the Ruby-flies attain a large size, they are usually very conspicuous on account of their gaudy or brilliant colours. They are amongst the most restless and rapid of Insects; {3}they love the hot sunshine, and are difficult of capture. Though not anywhere numerous in species, they are found in most parts of the world. In Britain we have about twenty species. They usually frequent old wood or masonry, in which the nests of Aculeate Hymenoptera exist, or fly rapidly to and fro about the banks of earth where bees nest. Dr. Chapman has observed the habits of some of our British species.[2] He noticed _Chrysis ignita_ flying about the cell of _Odynerus parietum_, a solitary wasp that provisions its nest with caterpillars; in this cell the _Chrysis_ deposited an egg, and in less than an hour the wasp had sealed the cell. Two days afterwards this was opened and was found to contain a larva of _Chrysis_ a quarter of an inch long, as well as the Lepidopterous larvae stored up by the wasp, but there was no trace of egg or young of the wasp. Six days after the egg was laid the _Chrysis_ had eaten all the food and was full-grown, having moulted three or four times. Afterwards it formed a cocoon in which to complete its metamorphosis. It is, however, more usual for the species of _Chrysis_ to live on the larva of the wasp and not on the food; indeed, it has recently been positively stated that _Chrysis_ never eats the food in the wasp's cell, but there is no ground whatever for rejecting the evidence of so careful an observer as Dr. Chapman. According to M. du Buysson the larva of _Chrysis_ will not eat the lepidopterous larvae, but will die in their midst if the _Odynerus_ larva does not develop; but this observation probably relates only to such species as habitually live on _Odynerus_ itself. The mother-wasp of _Chrysis bidentata_ searches for a cell of _Odynerus spinipes_ that has not been properly closed, and that contains a full-grown larva of that wasp enclosed in its cocoon. Having succeeded in its search the _Chrysis_ deposits several eggs—from six to ten; for some reason that is not apparent all but one of these eggs fail to produce young; in two or three days this one hatches, the others shrivelling up. The young _Chrysis_ larva seizes with its mouth a fold of the skin of the helpless larva of the _Odynerus_, and sucks it without inflicting any visible wound. In about eleven days the _Chrysis_ has changed its skin four times, has consumed all the larva and is full-fed; it spins its own cocoon inside that of its victim, and remains therein till the following spring, when it changes to a pupa, and in less than three weeks {4}thereafter emerges a perfect _Chrysis_ of the most brilliant colour, and if it be a female indefatigable in activity. It is remarkable that the larva of _Chrysis_ is so much like that of _Odynerus_ that the two can only be distinguished externally by the colour, the _Odynerus_ being yellow and the _Chrysis_ white; but this is only one of the many cases in which host and parasite are extremely similar to the eye. _Chrysis shanghaiensis_ has been reared from the cocoons of a Lepidopterous Insect—_Monema flavescens_, family Limacodidae—and it has been presumed that it eats the larva therein contained. All other Chrysids, so far as known, live at the expense of Hymenoptera (usually, as we have seen, actually consuming their bodies), and it is not impossible that _C. shanghaiensis_ really lives on a Hymenopterous parasite in the cocoon of the Lepidopteron.

_Parnopes carnea_ frequents the nests of _Bembex rostrata_, a solitary wasp that has the unusual habit of bringing from time to time a supply of food to its young larva; for this purpose it has to open the nest in which its young is enclosed, and the _Parnopes_ takes advantage of this habit by entering the cell and depositing there an egg which produces a larva that devours that of the _Bembex_. The species of the anomalous genus _Cleptes_ live, it is believed, at the expense of Tenthredinidae, and in all probability oviposit in their cocoons which are placed in the earth.

SERIES 3. HYMENOPTERA ACULEATA.

_The females (whether workers or true females) provided with a sting:
trochanters usually undivided (monotrochous). Usually the antennae of the
males with thirteen, of the females with twelve, joints (exceptions in
ants numerous)._

These characters only define this series in a very unsatisfactory manner, as no means of distinguishing the "sting" from the homologous structures found in Tubulifera, and in the Proctotrypid division of Hymenoptera Parasitica, have been pointed out. As the structure of the trochanters is subject to numerous exceptions, the classification at present existing is an arbitrary one. It would probably be more satisfactory to separate the Proctotrypidae (or a considerable part thereof) from the Parasitica, and unite them with the Tubulifera and Aculeata in a great series, characterised by the fact that the ovipositor is {5}withdrawn into the body in a direct manner so as to be entirely internal, whereas in the Parasitica it is not withdrawn in this manner, but remains truly an external organ, though in numerous cases concealed by a process of torsion of the terminal segments. If this were done it might be found possible to divide the great group thus formed into two divisions characterised by the fact that the ovipositor in one retains its function, the egg passing through it (Proctotrypidae and Tubulifera), while in the other the organ in question serves as a weapon of offence and defence, and does not act as a true ovipositor, the egg escaping at its base. It would, however, be premature to adopt so revolutionary a course until the comparative anatomy of the organs concerned shall have received a much greater share of attention; a detailed scrutiny of Prototrypidae being particularly desired.

We have dealt with the external anatomy of Hymenoptera in {6}Vol. V.; so that here it is only necessary to give a diagram to explain the terms used in the descriptions of the families and sub-families of Aculeata, and to discuss briefly their characteristic structures.

The Sting of the bee has been described in detail by Kraepelin, Sollmann, Carlet[3] and others. It is an extremely perfect mechanical arrangement. The sting itself—independent of the sheaths and adjuncts—consists of three elongate pieces, one of them a gouge-like director, the other two pointed and barbed needles; the director is provided with a bead for each of the needles to run on, these latter having a corresponding groove; the entrance to the groove is narrower than its subsequent diameter, so that the needles play up and down on the director with facility, but cannot be dragged away from it; each needle is provided with an arm at the base to which are attached the muscles for its movement. This simple manner of describing the mechanical arrangement is, however, incomplete, inasmuch as it includes no account of the means by which the poison is conveyed. This is done by a very complex set of modifications of all the parts; firstly, the director is enlarged at the anterior part to form a chamber, through which the needles play; the needles are each provided with a projecting piece, which, as the needle moves, plays in the chamber of the director, and forces downwards any liquid that may be therein; the poison-glands open into the chamber, and the projections on the needles, acting after the manner of a piston, carry the poison before them. The needles are so arranged on {7}the director that they enclose between themselves and it a space that forms the channel along which the poison flows, as it is carried forwards by the movement of the pistons attached to the needles. If the needles be thrust into an object quite as far as, or beyond, the point of the director much poison may be introduced into a wound, as the barbs are provided with small orifices placed one above the other, while if this be not the case much of the liquid will flow on the outside of the object.

According to Carlet the poison of the bee is formed by the mixture of the secretions of two glands, one of which is acid and the other alkaline; it is very deadly in its effects on other Insects. We shall see, however, that the Fossorial Hymenoptera, which catch and sting living prey for their young, frequently do not kill but only stupefy it, and Carlet states that in this group the alkaline gland is absent or atrophied, so that the poison consists only of the acid; it is thus, he thinks, deprived of its lethal power. Moreover, in the Fossoria the needles are destitute of barbs, so that the sting does not remain in the wound. Bordas, however, states[4] that in all the numerous Hymenoptera he has examined, both acid and alkaline glands exist, but exhibit considerable differences of form in the various groups. He gives no explanation of the variety of effects of the poison of different Aculeata.

The larvae (for figure of larva of _Bombus_, see Vol. V. p. 488) are, without known exception, legless grubs, of soft consistence, living entirely under cover, being protected either in cells, or, in the case of social Hymenoptera, in the abodes of the parents. The larvae of Ants and fossorial Hymenoptera have the anterior parts of the body long and narrow and abruptly flexed, so that their heads hang down in a helpless manner. All the larvae of Aculeates, so far as known, are remarkable from the fact that the posterior part of the alimentary canal does not connect with the stomach till the larval instar is more or less advanced; hence the food amongst which they live cannot be sullied by faecal matter. The pupa is invariably soft, and assumes gradually the colour of the perfect Insect. Almost nothing is known as to the intimate details of the metamorphosis, and very little as to the changes of external form. According to Packard a period intervenes between the stadium of the full-grown larva and that of the pupa, in which a series of changes he speaks of as semi-pupal {8}are passed through; these, however, have not been followed out in the case of any individual, and it is not possible to form any final idea about them, but it seems probable that they are largely changes of external shape, in conformity with the great changes going on in the internal organs. Owing to the fragmentary nature of observations, much obscurity and difference of opinion have existed as to the metamorphosis of Aculeate Hymenoptera. Sir S. Saunders gives the following statement as to the larva of a wasp of the genus _Psiliglossa_,[5] just before it assumes the pupal form: "The respective segments, which are very distinctly indicated, may be defined as follows:—The five anterior, including the head, are compactly welded together, and incapable of separate action in the pseudo-pupa state; the third, fourth, and fifth bearing a spiracle on either side. The thoracical region terminating here, the two anterior segments are assignable to the development of the imago head, as pointed out by Ratzeburg." This inference is not, however, correct. We have seen that in the perfect Insect of Petiolate Hymenoptera the first abdominal segment is fixed to the thorax, and Saunders' statement is interesting as showing that this assignment of parts already exists in the larva, but it in no way proves that the head of the imago is formed from the thorax of the larva. It has been stated that the larvae of the Aculeata have a different number of segments according to the sex, but this also is incorrect. The difference that exists in the perfect Insects in this respect is due to the withdrawal of the terminal three segments to the interior in the female, and of two only in the male. The larva consists of fourteen segments, and we find this number distributed in the female perfect Insect as follows: one constitutes the head, four segments the thorax and propodeum, followed by six external segments of the restricted abdomen, and three for the internal structures of the abdomen. This agrees with Forel's statement that in the ants the sting is placed in a chamber formed by three segments.

The development of the sting of the common bee has been studied by Dewitz.[6] It takes place in the last larval stage. Although nothing of the organ is visible externally in the adult larva, yet if such a larva be placed in spirit, there can be seen within the skin certain small appendages on the ventral surface of the penultimate and antepenultimate abdominal segments {9}(Fig. 4, A) placed two on the one, four on the other; these are the rudiments of the sting. In the course of development the terminal three segments are taken into the body, and the external pair of the appendages of the twelfth body segment (the ninth abdominal) become the sheaths of the sting, and the middle pair become the director; the pair of appendages on the eleventh segment give rise to the needles or spiculae. The sting-rudiments at an earlier stage (Fig. 4, C) are masses of hypodermis connected with tracheae; there is then but one pair on the twelfth segment, and this pair coalesce to form a single mass; the rudiments of the pair that form the director are differentiated secondarily from the primary pair of these masses of hypodermis. A good deal of discussion has taken place as to whether the component parts of the sting—gonapophyses—are to be considered as modifications of abdominal extremities (_i.e._ abdominal legs such as exist in Myriapods). Heymons is of opinion that this is not the case, but that the leg-rudiments and gonapophysal rudiments are quite distinct.[7] The origin of the sting of Hymenoptera (and of the ovipositor of parasitic Hymenoptera) is very similar to that of the ovipositor of _Locusta_ (Vol. V. p. 315 of this work), but there is much difference in the history of the development of the rudiments.

Dewitz has also traced the development of the thoracic appendages in Hymenoptera.[8] Although no legs are visible in the adult larva, they really arise very early in the larval life from masses of hypodermis, and grow in the interior of the body, so that when the larva is adult the legs exist in a segmented though rudimentary condition in the interior of the body. Dewitz's study of the wing-development is less complete.

{10}Four primary divisions of Aculeates are generally recognised, viz. Anthophila (Bees), Diploptera (Wasps), Fossores (Solitary Wasps), Heterogyna (Ants). Though apparently they are natural, it is impossible to define them by characters that are without some exceptions, especially in the case of the males. Ashmead has recently proposed[9] to divide the Fossores; thus making five divisions as follows:—

Body with more or less of the hairs on it plumose 1. Anthophila.

Hairs of body not plumose.

Pronotum not reaching back to tegulae 2. Entomophila
[= Fossores part].
Pronotum reaching back to tegulae.

Petiole (articulating segment of abdomen) simple without
scales or nodes.

Front wings in repose with a fold making them narrow
3. Diploptera.
Front wings not folded 4. Fossores [part].

Petiole with a scale or node (an irregular elevation
on the upper side) 5. Heterogyna.

We shall here follow the usual method of treating all the fossorial wasps as forming a single group, uniting Ashmead's Entomophila and Fossores, as we think their separation is only valid for the purposes of a table; the Pompilidae placed by the American savant in Fossores being as much allied to Entomophila as they are to the other Fossores with which Ashmead associates them.

DIVISION I. ANTHOPHILA OR APIDAE—BEES.

_Some of the hairs of the body plumose; parts of the mouth elongated,
sometimes to a great extent, so as to form a protrusible apparatus,
usually tubular with a very flexible tip. Basal joint of hind foot
elongate. No wingless adult forms; in some cases societies are formed,
and then barren females called workers exist in great numbers, and carry
on the industrial operations of the community. Food always derived from
the vegetable kingdom, or from other Bees._

There are about 150 genera and 1500 species of bees at present known. Some call the division Mellifera instead of Anthophila. The term Apidae is used by some authorities to denote all the bees, while others limit this term to one of the families {11}or sub-divisions. The bees are, as a rule, distinguished from other Hymenoptera by the hairs, by the great development of the mouth parts to form a proboscis (usually, but not correctly, called tongue), and by the modification of the hind-legs; but these distinctive characters are in some of the species exhibited in so minor a degree of perfection that it is not easy to recognise these primitive forms as Anthophila. A few general remarks on the three points mentioned will enable the student to better appreciate the importance of certain points we shall subsequently deal with.

The bees are, as a rule, much more covered with hair than any other of the Hymenoptera. Saunders[10] states that he has examined the structure of the hairs in all the genera of British Aculeata, and that in none but the Anthophila do branched and plumose hairs occur. The function of this kind of hairs is unknown; Saunders suggests[10] that they may be instrumental in the gathering of pollen, but they occur in the parasitic bees as well as in the males, neither of which gather pollen. The variety of the positions they occupy on the body seems to offer but little support to the suggestion. Not all the hairs of the bee's body are plumose, some are simple, as shown in Fig. 5, A, and this is specially the case with the hairs that are placed at the edges of the dilated plates for carrying pollen. In some forms there is an extensive system of simple hairs all over the body, and the "feathers" are distributed between these; and we do not see any reason for assuming that the feathered are superior to the simple hairs for gathering and carrying pollen. Some bees, _e.g._ _Prosopis_, _Ceratina_, have very little hair on the body, but nevertheless some plumose hairs are always present even though they be very short.

{12}

The hind-legs of bees are very largely used in the industrial occupations of these indefatigable creatures; one of their chief functions in the female being to act as receptacles for carrying pollen to the nest: they exhibit, however, considerable diversity. The parts most modified are the tibia and the first joint of the hind-foot. Pollen is carried by other parts of the body in many bees, and even the hind-leg itself is used in different ways for the purpose: sometimes the outer face of the tibia is highly polished and its margins surrounded by hair, in which case pollen plates are said to exist (Fig. 6, A); sometimes the first joint of the tarsus is analogous to the tibia both in structure and function; in other cases the hind-legs are thick and densely covered with hair that retains the pollen between the separate hairs. In this case the pollen is carried home in a dry state, while, in the species with pollen plates, the pollen is made into a mass of a clay-like consistence.[11] The legs also assist in arranging the pollen on the other parts of the body. The males do not carry pollen, and though their hind-legs are also highly modified, yet the modifications do not agree with those of the female, and their functions are in all probability sexual. The parasitic bees also do not carry pollen, and exhibit another series of structures. The most interesting case in this series of modifications is that found in the genus _Apis_, where the hind-leg of male, female, and worker are all different (Fig. 25); the limb in the worker being highly modified for industrial purposes. This case has been frequently referred to, in consequence of the difficulty that exists in connection with its heredity, for the {13}structure exists in neither of the parents. It is, in fact, a case of a very special adaptation appearing in the majority of the individuals of each generation, though nothing of the sort occurs in either parent.

The proboscis of the bee[12] is a very complex organ, and in its extremely developed forms exhibits a complication of details and a delicacy of structure that elicit the admiration of all who study it. In the lower bees, however, especially in _Prosopis_, it exists in a comparatively simple form (Fig. 9, B, C), that differs but little from what is seen in some Vespidae or Fossores. The upper lip and the mandibles do not take any part in the formation of the bee's proboscis, which is consequently entirely made up from the lower lip and the maxillae, the former of these two organs exhibiting the greatest modifications. The proboscis is situate on the lower part of the head, and in repose is not visible; a portion, and that by no means an inconsiderable one, of its modifications being for the purpose of its withdrawal and protection when not in use. For this object the under side of the head is provided with a very deep groove, in which the whole organ is, in bees with a short proboscis, withdrawn; in the Apidae with a long proboscis this groove also exists, and the basal part of the proboscis is buried in it during repose, while the other parts of the elongate organ are doubled on the basal part, so that they extend backwards under the body, and the front end or tip of the tongue is, when in repose, its most posterior part.

For the extrusion of the proboscis there exists a special apparatus that comes into play after the mandibles are unlocked and the labrum lifted. This extensive apparatus cannot be satisfactorily illustrated by a drawing, as the parts composing it are placed in different planes; but it may be described by saying that the cardo, or basal hinge of the maxilla, changes from an oblique to a vertical position, and thrusts the base of the proboscis out of the groove. The maxillae form the outer sheath of the proboscis, the lower lip its medial part (see Figs. 7 and 9); the base of the lower lip is attached to the submentum, which rises with the cardo so that labium and maxillae are lifted together; the co-operation of these two parts is effected by an angular piece called the lorum, in which the base of the submentum rests; the submentum is articulated with the mentum in such a manner that the two can either be placed in planes at a right angle to one another, or can be brought into one continuous plane, and by this change of plane the basal part of the tongue can also be thrust forwards.

{14}

There is considerable variety in the lengths of these parts in different genera, and the lorum varies in shape in accordance with the length of the submentum. The lorum is a peculiar piece, and its mechanical adaptations are very remarkable; usually the base of the submentum rests in the angle formed by the junction of the two sides of the lorum, but in _Xylocopa_, where the submentum is unusually short, this part reposes in a groove on the back of the lorum, this latter having a very broad truncated apex instead of an angular one; in the condition of repose the apex of the lorum rests in a notch on the middle of the back of the oral groove, and in some of the forms with elongate submentum, this depression is transformed into a deep hole, or even a sort of tunnel, so as to permit the complete stowing away of the base of the tongue, which would otherwise be prevented by the long submentum; another function of the lorum appears to be that, as it extends, its arms have an outward thrust, and so separate the maxillae from the labium. In addition to these parts there are also four elongate, slender sclerites that are only brought into view on dissection, and that no doubt assist in correlating the movements of the parts of the mouth and {15}hypopharynx; one pair of these strap-like pieces extends backwards from the two sides of the base of the epipharynx; Huxley called them sclerites of the oesophagus; a better name would be epipharyngeal sclerites (Fig. 7, _a_): the other pair pass from the terminations of the epipharyngeal sclerites, along the front face of the hypopharynx, down to the mentum, their lower parts being concealed by the stipites of the maxillae; these are the hypopharyngeal sclerites, and we believe it will prove that they play a highly important part in deglutition. When the labrum of a bee is raised and the proboscis depressed, the epipharynx is seen hanging like a curtain from the roof of the head; this structure plays an important part in the act of deglutition. The entrance to the pharynx, or commencement of the alimentary canal, is placed below the base of the epipharynx. As we are not aware of any good delineations of the basal parts of the proboscis we give a figure thereof (Fig. 7). The maxillae in the higher bees are extremely modified so as to form a sheath, and their palpi are minute; in the lower bees the palpi have the structure usual in mandibulate Insects.

Returning to the consideration of the lower lip, we find that there is attached to the mentum a pair of elongate organs that extend forwards and form a tube or sheath, enclosed by the maxillary sheath we have previously mentioned; these are the greatly modified labial palpi, their distal parts still retaining the palpar form; and in the lower bees the labial palpi are, like the maxillary, of the form usual in mandibulate Insects. Between the labial palps and the central organ of the lip there is attached a pair of delicate organs, the paraglossae.

There remains for consideration the most remarkable part of the proboscis, the long, delicate, hairy organ which the bee thrusts out from the tip of the shining tube formed by the labial palps and the maxillae, described above, and which looks like a prolongation of the mentum. This organ is variously called ligula, lingua, or tongue.[13] We prefer the first of these names.

According to Breithaupt and Cheshire the structure of the ligula is highly remarkable; it is a tube (filled with fluid from the body cavity), and with a groove underneath caused by a large part of the circumference of the tube being invaginated; the {16}invaginated part can be thrust out by increase of the pressure of the fluid in the tube. A portion of the wall of the invaginate part is thickened so as to form a chitinous rod.

This description will suffice for present purposes, as the other parts of the mouth will be readily recognised by the aid of figure 9, A, B, C. In the exquisitely endowed South American genus _Euglossa_ (Fig. 18), the proboscis is somewhat longer than the whole of the body, so that its tip in repose projects behind the body like a sting.

The correct nomenclature of the parts connected with the lower lip is not definitely settled, authorities not being agreed on several points. The whole of the proboscis is usually called the tongue; this, however, is admittedly an erroneous application of this term. The terminal delicate, elongate, flexible organ is by some called the tongue; but this again is wrong: the lingua in Insects is the hypopharynx; this part is developed in a peculiar manner in bees, but as it is not tongue-like in shape, the term lingua is not suitable for it, and should be dismissed altogether from the nomenclature of the bee's trophi; it is used at present in two different senses, both of which are erroneous. We see no objection to describing the flexible apical portion of the proboscis as the ligula. The lorum is probably a special part peculiar to the higher bees; according to Saunders it is not present as a specialised part in some of the primitive forms.[14] The application of the terms mentum, submentum and hypoglottis is open to the same doubts that exist with regard to them in so many other {17}Insects, and we have omitted the term hypoglottis altogether, though some may think the mentum entitled to that name.

The way in which the proboscis of the bee acts has been very largely discussed, with special reference to the question as to whether it is a sucking or a licking action. It is impossible to consider either of these terms as applicable. The foundation of the action is capillary attraction, by which, and by slight movements of increase and contraction of the capacity of various parts, the fluid travels to the cavity in front of the hypopharynx: here the scales of the maxillae leave a vacant space, (Fig. 7, _e_) so that a cup or cavity is formed, the fluid in which is within reach of the tip of the dependent epipharynx (_c_), which hangs down over the front of the hypopharynx (and is so shaped that its tip covers the cup); it is between these two parts that the fluid passes to reach the pharynx. It is no doubt to slight movements of the membranous parts of the hypopharynx and of the epipharynx that the further progress of the nectar is due, aided by contraction and expansion of the pharynx, induced by muscles attached to it. It should be recollected that in addition to the movements of the head itself, the hypopharynx is constantly changing its dimensions slightly by the impulses of the fluid of the general body cavity; also that the head changes its position, {18}and that the proboscis is directed downwards as well as forwards. Those who wish to pursue this subject should refer to the works of Breithaupt[15] and Cheshire.

The other external characters of the Bees call for little remark. The pronotum is never very large or much prolonged in front, and its hind angles never repose on the tegulae as they do in the wasps,[16] but extend backwards below the tegulae. The hind body is never narrowed at the base into an elongate pedicel, as it so frequently is in the Wasps and in the Fossors; and the propodeum (the posterior part of the thorax) is more perpendicular and rarely so largely developed as it is in the Fossors; this last character will as a rule permit a bee to be recognised at a glance from the fossorial Hymenoptera.

Bees, as every one knows, frequent flowers, and it is usually incorrectly said that they extract honey. They really gather nectar, swallow it, so that it goes as far as the crop of their alimentary canal, called in English the honey-sac, and is regurgitated as honey. Bertrand states that the nectar when gathered is almost entirely pure saccharose, and that when regurgitated it is found to consist of dextrose and levulose:[17] this change appears to be practically the conversion of cane- into grape-sugar. A small quantity of the products of the salivary glands is added, and this probably causes the change alluded to; so that honey and nectar are by no means synonymous. According to Cheshire the glandular matter is added while the nectar is being sucked, and is passing over the middle parts of the lower lip, so that the nectar may be honey when swallowed by the bee. In addition to gathering nectar the female bees are largely occupied in collecting pollen, which, mixed with honey, is to serve as food for the colony. Many, if not all, bees eat pollen while collecting it. The mode in which they accumulate the pollen, and the mechanism of its conveyance from hair to hair till it reaches the part of the body it must attain in order to be removed for packing in the cells, is not fully understood, but it appears to be accomplished by complex correlative actions of various parts; the head and the front legs scratch up the pollen, the legs move with great rapidity, and the pollen ultimately reaches its destination. The workers of the genus _Apis_, and of some other social {19}bees, have the basal joint of the hind foot specially adapted to deal with pollen (Fig. 25, 2). We have already mentioned the modifications of the legs used for its conveyance, and need here only add that numerous bees—the Dasygastres—carry the pollen by aid of a special and dense clothing of hairs on the underside of the abdomen.

The buzzing of bees (and other Insects) has been for long a subject of controversy: some having maintained that it is partially or wholly due to the vibration of parts connected with the spiracles, while others have found its cause in the vibrations of the wings. According to the observations of Pérez and Bellesme,[18] two distinct sounds are to be distinguished. One, a deep noise, is due to the vibration of the wings, and is produced whenever a certain rapidity is attained; the other is an acute sound, and is said to be produced by the vibrations of the walls of the thorax, to which muscles are attached; this sound is specially evident in Diptera and Hymenoptera, because the integument is of the right consistence for vibration. Both of these observers agree that the spiracles are not concerned in the matter.

The young of bees are invariably reared in cells. These (except in the case of the parasitical bees) are constructed by the mothers, or by the transformed females called workers. The solitary bees store the cells with food, and close up each cell after having laid an egg in it, so that in these cases each larva consumes a special store previously provided for it. The social bees do not close the cells in which the larvae are placed, and the workers act as foster-mothers, feeding the young larvae after the same fashion as birds feed their nestling young. The food is a mixture of honey and pollen, the mixing being effected in various ways and proportions according to the species; the honey seems to be particularly suitable to the digestive organs of the young larvae, and those bees that make closed cells, place on the outside of the mass of food a layer more thickly saturated with honey, and this layer the young grub consumes before attacking the drier parts of the provisions. The active life of the larva is quite short, but after the larva is full-grown it usually passes a more or less prolonged period in a state of quiescence before assuming the pupal form. The pupa shows the limbs and other parts of the perfect Insect in a very distinct manner, and the {20}development of the imago takes place gradually though quickly. Some larvae spin cocoons, others do not.

A very large number of bees are parasitic in their habits, laying an egg, or sometimes more than one, in the cell of a working bee of some species other than their own; in such cases the resulting larvae eat and grow more quickly than the progeny of the host bee, and so cause it to die of starvation. It has been observed that some of these parasitic larvae, after eating all the store of food, then devour the larva they have robbed. In other cases it is possible that the first care of the parasitic larva, after hatching, is to eat the rival egg.

The taxonomy of bees is in a very unsatisfactory state. The earlier Hymenopterists were divided into two schools, one of which proposed to classify the bees according to their habits, while the other adopted an arrangement depending on the length of the parts of the mouth, the development of the palpi, and the form and positions of the organs for carrying pollen. Neither of these arrangements was at all satisfactory, and some entomologists endeavoured to combine them, the result being a classification founded partly on habits and partly on certain minor structural characters. This course has also proved unsatisfactory; this is especially the case with exotic bees, which have been placed in groups that are defined by habits, although very little observation has actually been made on this point. Efforts have recently been made to establish an improved classification, but as they relate solely to the European bees they are insufficient for general purposes.

The more important of the groups that have been recognised are—(1) the Obtusilingues, short-tongued bees, with the tip of the lingua bifid or broad; (2) Acutilingues, short-tongued bees, with acute tip to the tongue; these two groups being frequently treated of as forming the Andrenidae. Coming to the Apidae, or the bees with long and folded tongues, there have been distinguished (3) Scopulipedes, bees carrying pollen with their feet, and (4) Dasygastres, those that carry it under the abdomen; some of the parasitic and other forms have been separated as (5) Denudatae (or Cuculinae); the Bombi and the more perfectly social bees forming another group, viz. (6) Sociales. A group Andrenoides, or Panurgides, was also proposed for certain bees considered to belong to the Apidae though exhibiting many points of {21}resemblance with the Andrenidae. This arrangement is by no means satisfactory, but as the tropical bees have been but little collected, and are only very imperfectly known, it is clear that we cannot hope for a better classification till collections have been very much increased and improved. The arrangement adopted in Dalla Torre's recent valuable catalogue of bees[19] recognises no less than fourteen primary divisions, but is far from satisfactory.

The two genera _Prosopis_ and _Sphecodes_ have been recently formed into a special family, Archiapidae, by Friese,[20] who, however, admits that the association is not a natural one. The term should be limited to _Prosopis_ and the genera into which it has been, or shortly will be, divided. The primitive nature of the members of this genus is exhibited in all the external characters that are most distinctive of bees; the proboscis (Fig. 9, B, C), is quite short, its ligula being very short, and instead of being pointed having a concave front margin. The body is almost bare, though there is some very short feathered plumage. The hind legs are destitute of modifications for industrial purposes. Owing to these peculiarities it was for long assumed that the species of _Prosopis_ must be parasites. This is, however, known not to be the case so far as many of the species are concerned. They form cells lined with a silken membrane in the stems of brambles and other plants that are suitable, or in burrows in the earth, or in the mortar of walls; individuals of the same species varying much as to the nidus they select. The food they store in these cells is much more liquid than usual, and has been supposed to be entirely honey, since they have no apparatus for carrying pollen. Mr. R. C. L. Perkins has, however, observed that they swallow both pollen and nectar, brushing the first-named substance to the mouth by aid of the front legs. He {22}has ascertained that a few of the very numerous Hawaiian species of the genus are really parasitic on their congeners: these parasites are destitute of a peculiar arrangement of hairs on the front legs of the female, the possession of which, by some of the non-parasitic forms, enables the bee to sweep the pollen towards its mouth. These observations show that the structural peculiarities of _Prosopis_ are correlative with the habits of forming a peculiar lining to the cell, and of gathering pollen by the mouth and conveying it by the alimentary canal instead of by external parts of the body. _Prosopis_ is a very widely distributed genus, and very numerous in species. We have ten in Britain; several of them occur in the grounds of our Museum at Cambridge.

The species of the genus _Colletes_ are hairy bees of moderate size, with a good development of hair on the middle and posterior femora for carrying pollen. They have a short, bilobed ligula like that of wasps, and therein differ from the Andrenae, which they much resemble. With _Prosopis_ they form the group Obtusilingues of some taxonomists. They have a manner of nesting peculiar to themselves; they dig cylindrical burrows in the earth, line them with a sort of slime, that dries to a substance like gold-beater's skin, and then by partitions arrange the burrow as six to ten separate cells, each of which is filled with food that is more liquid than usual in bees. Except in regard to the ligula and the nature of the cell-lining, _Colletes_ has but little resemblance to _Prosopis_; but the term Obtusilingues may be applied to _Colletes_ if _Prosopis_ be separated as Archiapidae. We have six species of _Colletes_ in Britain.

_Sphecodes_ is a genus that has been the subject of prolonged difference of opinion. The species are rather small shining bees, with a red, or red and black, abdomen, almost without pollen-collecting apparatus, and with a short but pointed ligula. These characters led to the belief that the Insects are parasitic, or, as they are sometimes called, cuckoo-bees. But evidence could not be obtained of the fact, and as they were seen to make burrows it was decided that we have in _Sphecodes_ examples of industrial bees extremely ill endowed for their work. Recent observations tend, however, to prove that _Sphecodes_ are to a large extent parasitic at the expense of bees of the genera _Halictus_ and _Andrena_. Breitenbach has taken _S. rubicundus_ out of the brood-cells of _Halictus quadricinctus_; and on one of the few {23}occasions on which this bee has been found in Britain it was in circumstances that left little doubt as to its being a parasite of _Andrena nigroaenea_. Marchal[21] has seen _S. subquadratus_ fight with _Halictus malachurus_, and kill it previous to taking possession of its burrows; and similar observations have been made by Ferton. As the older observations of Smith, Sichel, and Friese leave little doubt that _Sphecodes_ are sometimes industrial bees, it is highly probable that we have in this genus the interesting condition of bees that are sometimes parasitic, at other times not; but so much obscurity still prevails as to the habits of _Sphecodes_ that we should do well to delay accepting the theories that have been already based on this strange state of matters.[22] Friese states that in _Sphecodes_ the first traces of collecting apparatus exist; and, accepting the condition of affairs as being that mentioned above, it is by no means clear whether we have in _Sphecodes_ bees that are abandoning the parasitic habit or commencing it; or, indeed, whether the condition of uncertainty may not be a permanent one. It is difficult to decide as to what forms are species in _Sphecodes_ owing to the great variation. The Hymenopterist Forster considered that 600 specimens submitted to him by Sichel represented no less than 140 species, though Sichel was convinced that nearly the whole of them were one species, _S. gibbus_. It has recently been found that the male sexual organs afford a satisfactory criterion. The position of _Sphecodes_ in classification is doubtful.