D EPOSITED BY THE FACULTY OF GRADUATE STUDIES AND RESEARCH. c.\ M~ GILL UNIVERSITY. LIBRARY ACC. NO.

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2 D EPOSITED BY THE FACULTY OF GRADUATE STUDIES AND RESEARCH c.\ M~ GILL UNIVERSITY. LIBRARY ACC. NO.

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4 THE :MORPHOLOGY OF HALICTUS LEROUXI LEP BY J. VJ. I;I. CA.ThrERON A THESIS Submitted to the Faculty of Graduate studies and Research of ~.fcgill University in Partial Fulfilfment of the Requirements for the Degree of ~.r.sc. April, 1932.

5 The Morphology of Halictua lerouxi, Le p. By J.w.n. Cameron (Author's Abstract). the_ This paper coversaexternal and part of the internal anatomy of Halictus lerouxi LeP., a small solitary bee found in large numbers in the fruit belt of Nova Sootia. The structures throughout are compared with those of the honey bee, and closely resemble them in most cases. laofnia of the maxilla is apparently absent. tentorium bears a pair of dorsal arms, and the anterior and posterior arms of the two sides are connected by a V-shaped lamella. The The The thorax consists of the usual three segments plus the first abdominal segment or propodeum. abdomen consists of nine segments, including the propodeum. The genital segments are invaginated within the six$ih and seventh. The The reproductive and digestive systems closely resembl~ those of the honey bee in general structure. The testes have become fused on the median line. There are more glands present in connection with the digestive system than is the case in A mellifica. The central nervous system has only four abdominal ganglia.

6 C 0 N T E N T s. Page I INTRODUCTION 1 II. EXTERNAL ANATOliiY A. Head 1. General External Structure 3 2. _Mouthparta 4 3. Antennae 7 4. Endocranium 8 B. Thorax. 1. General Structure a a. Pro thorax 9 b. l!esothorax 10 c. Metathorax 11 d. Propodeum Wings Legs Endothorax 17 c. Abdomen 1. General structure Genital Structures a. Female (Sting) 20 b. :D.iale 22 III INTERNAL ANATOMY. A. Digestive System 1. Digestive Tract Glands 26 B. Nervous System 27

7 Page c. Reproductive System IV. SU:MMARY 1. Hale 2. Female V..&CKNOY:rLEDGEMENTS VI. BIBLIOGRAPHY

8 I - INTRODUCTION. The study of the morphology of Halictus lerouxi was undertaken following four seasons spent working under nr. W.H. Brittain investigat~g by insects. the pollination of_apples~ During the course of these investigations it was found th~ t the so 1 i ta.ry be ea form a ve-ry important factor in the proper pollination of the apple blossoms, and more particul~rly Halictus and Andrena. the species belonging to the genera. The nests of H. lerouxi occur in two distinct types of habitat: dry, sandy soil, firm and sparsely covered with vegetation; and heavy, firm clay, almost bare. One place in which they were very abundant was the inner face of a dyke wall, where the soil was of the latter description. ~ The holes are similar to those of H gra.terus except that they are slightly larger. polleb pellets are also very s~milar. The cells and (Plate I), Apparently there are two broods during the year, the first emerging about the middle of July, after which pellets and larvae are found for another month. No males were fouu1d in the holes, but in the latter part of July they were present in small numbers on the wing, while by the 11th of August they were found literally in thousands. of a month. ~mting occurs over a period Some females dig new holes in which to hibernate, while others simply deepen the summer holes, making them usually from eight to twelve inches. latter part of August. (Brittain, 1931). Hibernation begins during the

9 The present study is intended to be purely morphological, no attempt having been made to study the biology. Unfortunately the material used was not perfectly preserved, and it was found impossible to study the musaular, circulatory and respiratory systems. In the nervous system also only the main nerve trunks could be seen, and in the brain only the antennal nerves were sufficiently well preserved to be dissected out. It was found impossible to trace the ducts of the various glands.to their outlets for the same reason.

10 3. II EXTERNAL ANATOMY A. Head. 1. General External structure. The general structure of the head of the male is shown in figures 1, 2 and 3. female the head is more rounded, broader and shorter. In the The facial aspect of the head ia more or less triangular in outline, with the_ apex directed ventrally. It is somewhat convex, while the posterior surface is hollowed out to fit snugly over the anterior end of the thorax. The large compound e,yea (e) make - up the lateral margins ~t~ the head. The three ocelli (~) are situated on the vertex, the median one being in front of the other two. compound eyes just above the frons (f) The antennae (~) arise between the Their bases are quite close together and are inserted in two small, membranous so~akets in the head wall. The stem of the epicranial suture (~) has disappeared dorsad of the median ocel1us-. Its lower end bifurcates to enclose the frons (!) a:qd tbe clypeus (.2,!J. These latter are separated by the fronto-clypeal suture (foa), just above which may be faintly seen, in a head that has been boiled in caustic potash, the outline of the frontal plate (f ). This gives the frons the appearance of being divided by a u-shaped suture. The ends of the fronto-clypeal suture (fcs}, after meeting the - arms of the epicranial suture, are directed downward, and in ea~h end there is a small depression. These are the anterior tentorial invaginations (a.ti), marking the points of - origin of the anterior arms of the tentorium. The clypeus (cl) is a large plate below the frons, extending below the gena on either side. Attached to its lower margin is the

11 4. narrow, transverse labrum (!) bearing the epipharynx -,- on its under surface (fig. 12). The mandibles {md) are hinged to the sides of the head below the compound eyes, and between their bases is the mouth opening. The other mouthparts form the proboscis, attached to the lower side of the head, which will be described later. The caudal surface of the head (fig. 2), as stated above, is somewhat hollowed out, and in its natural position fits cap-like over the p~othorax. Occupying the canter of this hollow is the occipital foramen (of). - surrounded by the thickened edge of the rather broad postocciput (~) The pos_tocoiput is separated from the occiput (~)'and the postgenae (~) by the postocoipital suture (pos) in which are situated the posterior invaginations of the tentorium <!!) The postgenae meet below the po~tocciput, the edges being directed inward to form a fossa into which the proboscis is folded when not in use. 2. 1Iouth;parts. The mandibles (figs. 4, 33) are strong, jaw-like organs, having two ball-and-socket -- articulations (aa, oo) with the gena below the compound eye. The anterior articulation is by an acetabalum on the mandible and a condyle on the gena, while the posterior articulation has the structures reversed. The acet,abula are quite shallow. This arrangement allows free lateral motion of the mandibles, and enough longitudinal movement to allow one to pass by the other when they are brought

12 5. together. In the male {fig. 4} the mandibles are quite sharply pointed, while in the female (fig. 33) they are about twice as large as in the male and bear a blunt tooth C!) on the outer margin. The mand iblea are hollow, and are connected around the base w.ith the body wall by a membrane. The proboscis (figa. 5, 10) is made up of the maxillae and the labium, which are greatly elongated. The maxillae consist of cardo, stipes, galea and palp. The oardines ( ) are elongated and narrow and articulate with short, blunt processes which project downward from the anterior ends of' the anterior tentorial arms. They are invested in a membrane which also contains the lorum (lr) of the labium. The,stipites (~) articulate with the cardines, and bear along their upper margins the galeae (~) and at their dista.l extremities the palps (mxplp). Each galea is divided distally into an exogalea and an endogalea (fig. 8, exg, endg), a condition found in other Hymenoptera by Crampton (1923). The exoga1ea bears a fringe of quite long hairs. The palp is stx-segmented, apparently without anw distinct parifer., No lacinia was found, and its presence in this group seems to be controversial. r.mms (1925) states definitely that it is present in Apis ~llifioa, although often overlooked. MacGilli7ray (1912) also claims to have found it in the bee. Snodgrass m~ntions it in neither of his two works (1910, 1925) on the anatomy of the honey bee, although he figures the structure so described by the above workers. In the first reference (1910) he says "we have left only the terminal

13 6. blade-like lobe to account for, and it is evident that it must be either the galea or the lacinia or these two lobes combined. Here again a comparative knowledge of the mouthparts of Hymenoptera comes to our aid and shows clearly that the part in question is the outer lobe or galea, for the inner one becomes smaller and smaller in the higher members of the order and finally disappearsn. In the work published in 1925 he states definitely that the laoinia ~ has disappeared in ~ Andrena carlini, and in his discussion of the proboscis of the honey bee he does not mention it at all. Unless it has become greatly modified in Halictus lerouxi to form the chi tinous rod (figs. 5, 10, ~1) extends up into the membrane of the basal part of the proboscis, it has app.arently disappeared. The labium (figs. 5, 10, lb) is made up of the fused second maxillae, and consists of mentum, glossa, para,glossae and labial pal:p s. It is supported at the \7hioh base by the lorum (fig. 11, ~). ~he hypopharynx (hph) is borne at the distal end of the mentum between the pa.raglosaae. The mentum ie a long, more or less oylindrical organ, connected at the base by a membrane with the maxillae and with the lorum. apparently disappeared. The aubmentum has Looked at in cross-section (fig. 7) the mentum seems to consist of three fairly heavily sclerotized pieces, one ventrally and two dorsally, connected by areas which appear to be membranous. The glossa (figs. 6, 9, ~) glossae of the generalized mouthparts. consists of the two fused It is covered with

14 7. fine hairs and has many fine cross-striations, and the edges are curved downward and inward until they almost meet on the mid-ventral line. snodgrass (1925) describes this structure in the honey bee as being a conduit for the discharge of saliva. The paraglosaae (~) are two small, curved structures, one on either side of the glosse. at its base, and lying between the four-segmented labial palps. Between their bas.es, on the dis tal end of the menttun, is borne the small, _tongue-like hypopharynx, most easily seen in side view (fig. 10, hph). paraglosaae together form the ligula. The glossa and the two The base of the proboso_is lies in the loose, tubular membrane which connects the maxillae and the lorum, and whieh is attached to the stipites and the mentum near their bases. From each stipee and from each side of the mentum arises a chitinous rod {fig. 5 rl r2) which extends t..::::.j - up through this membrane, ending just below the lower end of the epipharynx. of muscles. These apparently serve for the attachment 3. Antennae. The antennae of the male are considerably longer than are those of the female, as may be seen by comparing figures 13 and 14. In the male the flagellum consists of twelve, and in the female of eleven, segments. The soape of the female antenna. is about one and one-half times as long as that of the male, and is slightly curved. It bears a number of quite ~long closely covered with very fine hairs. hairs, and the flagellum is

15 8. 4. Endocranium. The endoskeleton or tentorium of the head (figs. 15, 16} consists of three pairs of arms, anterior, posterior and-dorsal, and some secondary structures. The anterior arms (~) are stout bars arising as invaginations in the ends of the fronto-clypeal suture (fig. 1, ati). They extend back to meet the short posterior arms (E!)which arise as invaginations one on either side of the occipital foramen. (Fig. 2, pti}. At the point of union of these two there is given off on each side a slender dorsal arm (~) which is inserted just behind the antenna of the corresponding side. The body of the tentorium (fig. 16, btj is a slender bar arching across the occipital foramen and joining the two points of union of anterior and posterior arms. The ends of the anterio~ arms at their origins are united by a broad frontal plate (! ) which lies on the under surface of the frons. ~here is also a thin lamella (la) given off from the ventro-median side of the anterior and posterior arms, the tm lamellae meeting for a part of their length, to form a V-shaped trough in vjhich the sub-oesophageal ganglion and the digestive tube lie; the apex of the V is connected with the median line of the fossa of the proboscis by a single thin lamella. Through the opening between the lamellae and the frontal plate the pharynx passes. B. Thorax. 1. General Structure. The thorax of H. lerouxi (figs. 17, 25, 26), as in all of the higher Hymenoptera,

16 consists of the tbree.thoracic segments plus the propodeum or first abdominal segment. The whole structure, except the pleura-eternal parts of the prothorax, forma a oompact structure supporting the wings a:nd the middle and hind legs. a. Prothorax. The pleuro-sternum of the prothorax is en,irely separated from the no~ by an infolded membrane. The pleuron consists of a large, more or less quadrilateral plate articulating VJith the head by means of the cervical sclerites which have become fused with its anterior angles. {figs. 17, 26,!) The coxae of the fore-legs articulate with the posterior angles. The ventral edges are curved mesally, and the two pleura almost meet on the mid~ventral line. A line, probably representing the pleural suture (pe), extends from the coxa to the fusion with the cervical salerite. If this is the pleural suture, the narrow part above it would represent the epimeron (epm) and the. broad plate on the venter would be the episternum (~). The sternum of the prothorax (fig. 26, a 1 ) is a small padrilateral plate, in the natural position almost covered by the large coxae. Along the mid-ventral line there is a groove containing near the middle a de~p invagination {rf 1 ). This is the root of the furca, a structure which will be described later. The pronotum is closely connected with the segment behind it. It is divided into an anterior scutum (figs. 17, 25, _sc1} and a posterior scutellum (sctl). The soutellum bears on each side a large posteriorly - projecting plate or wing(!}, and is produced ventrally so that the two ends almost

17 10. meet on the mid-ventral line. The ends are covered by the coxae (fig. 26). b. Mesothora.x. The mesothor ax, (figs. 17, 25, 26) is the largest of the thoracic segments, and bears the larger of the two pairs of wings, as well as a pair of legs. The notum is divided by a suture, {figs. 17, 25, ~) into scutum {scg) and scutellum (sctl2) There is a secondary suture (!!} Which cuts off the postero-lateral angles of the scutum. Snodgrass {1911, 1925) at first called this the true scutosoutellar suture, considering the suture ~ to be secondary. Later, however, ( 1927) he discarded this view,.interpreting these sutures_ as given above. lmms ( 1925), however, holds with 3nodgrass's earlier interpretation, calling the small scleritea thus cut off the axillae. There is also another secondary suture (~2) on each side extending from the first, just above the bases of the wings, to the tegulae. These cut of the parapaidea (E!) which bear the anterior notal wing processes (anp, ). The scutellum is a narrow sclerite behind the scutum. It has its lateral extremities prolonged into the axillary cords of the front wings. The lateral extremities also bear the posterior notal wing processes (pnp 1 ). The postscutellum is sunken within the thorax and extends backward into the propodeum.- {fig. 32). It bears the large postphragma (poph). It is connec_ted with the s:cutellu.m by a small secondary sclerite x. The mesopleuro.n is a large plate on either side of the meeothorax. It i~ not divided from the sternum by a suture,

18 11. but extends continuously around to meet the corresponding plat~ from the o~her side dn the mid-ventral line. A furrow (~) near the anterior margin divides it superficially into two parts. On the dorsal margin it bears a large wing process (~1) with which the second axillary sc.lerite of the wing articulates. The spiracle (~} of the mesothorax is borne on the pleuron. The. pleural suture dividing the pleuron into episternum and epimeron could not be definitely identified. A suture-like mark appears on the pleural plate extending from the upper end of the furrow (fu) to the posterior margin. The position of this line is similar to that ocaupied by the pleural suture in the honey bee {Snodgrass, 1925), and it is possible that the two are homolog-ous. If this is the pleural suture the large plate below it continuous with the sternum would be the episternum, and the small plate bearing the ~ing process would be the epimeron. The sternum (fig. 26), as stated above, is not distinctly divided from the pleuron, forming with it the pleuro-sternal plate (~) of the segment. in which are two deep pits C!:f 2 }. the mesothoracio f'urca. It covers the ventral part Along the mid-ventral line is a suture These are the roots of On the posterior edge of the sternum, where the coxae are inserted, are two condyles {~ 2 ), either fossa. coxae with the sternum. These serve for the articulation of the one on c. lietathorax. ~he third segment or metathorax, lying between the mesothorax and the propodeum, is greatly reduced. It consists of a narrow tergum (fig. 25, ~\n) extending aciross the dorsum and bearing the wings at its

19 12. lateral extremitles; two pleura (fig. 17, eps3}, one on either side; and a small sternum (fig. 26,!3) The tergnm consists of a scutum only, and curves oaudally as it extends aaross the dorsum. The wings articulate with two processes, en anterior (anp 2,) and a posterior (pnp2), at each end~of the tergum. The metapleura {fig. 17, eps 3 ) are long, narrow, pointed sclerites.~directed postero-ventrally from the ends of the.:: tergum to the bases of the lege. At the upper end each bears a wing process C!E 2 ) and about one third of the distance from the dorsal end. of the posterior margin, sunken into the suture between the metathorax and the propodeum.., is a spiraole (!]_). At the lower end the pleuron is divided by a fold, the lower part being continuous through the antecoxal bridge ~ith the sternum. The sternum (fig. 26, _S3) is small, hexagonal, and continuous with the pleura as described above. Along the median line is a groove bearing the furcal pit (rf3). On the posterior margin are two oondyles, (cc3) one in each leg fossa, for the articulation of the coxae. d. Propodeum. The propodeum, which forms the posterior segment of the thoracic division of the body, is in reality the first abdominal segment. It consists largely of the tergum (figs. 17, 25 IT), which forms the upper and posterior lateral parts of the segment,sloping down to the peduncle. It contains a large spiraole (~) borne near the anterior angle. The sternum (fig. 26, ~) is quite small and very faintly sclerotized, and lies between the coxae of the metathoracic legs. - /

20 Wings. The wings are articulated vjith the thorax by means of small axillary sclerites. There are four of these in the front wing (fig. 36) and three in the hind wing (fig. 38}. The articulation is the same as in the honey bee. The first axillary sclerite articulates with the anterior notal wing process; the second forms the pivotal element of the wing base, articulating with the pleural wing pr-ocess. The third sclerite of the front wing is loosely articulated with the fourth, and forms the point of insertion~ of ope of the wing muscles. In the hind wing it articulates with the posterior notal wing process, corresponding thus to the fourth sclerite of the front wing. All these sclerites also articulate loosely with each other. There are, in addit-ion to these, two secondary sclerites in the hind wing and one in the front wing. ( figs. 36, 38, z) Covering the &nterior root of the fore wing is a hairy pad or tegula (fig. 17, tgl). The posterior margin of the membrane of the wing is continuous with the tergum of the thorax by the axillary cord. The wing venation in this epeoies is very greatly modified from the primitive type, as in.other Hymenoptera. It closely resembles that found in the honey bee, and may-~e beat understood by reference to figures 35 and 37. The condition found in the front wing is practically exactly the same as in Apis, but in the hind wing there is one vein more than in the honey bee. This has been tentatively labeled M1, but a comparative study ~uld be necessary to

21 14. determine whether or not this is correct. The hind wing has, along the anterior margin just beyond the point where the vein Rs + lt bends away from the margin, a row of small hooks or hamuli (fig. 37,!!) by means of which it is fastened to the fore-wing during flight. The number of these hamuli varies frpm nine to twelve in the male and from ten to thirteen i~ the female, and the number also varies on the two hind wings of the same _insect. In addition to this group there are several hamuli scattered along the margin towards the base of the wing. The hamttli hook under a thickened ridge on the anal margin of the fore-wing, just proxi~ad of the end of the first an~l vein, and thus insure synchronous action of the two wings during fl~ght. 3. Legs. The legs are shown in figures 18, 20 and 21, the views shown being the posterior surface of the fora and hind lags, and the anterior surface of the middle leg. One pair of lege is borne on each true thoracic segment. Each leg consists of a coxa, trochanter, femur, tibia and tarsus, and each has developed various accessory structures, mainly for use in gathering pollen. In all three pairs of legs the first joint of the five-jointed tarsus has become greatly elongated and enlarged. The next three joints are about normal, and the distal one is somewhat longer and I curved, and carries the terminal foot structures. The fore-leg (fig. 18) is somewhat shorter than the other two, and has a greater range of movement, due to the faot that the supporting parts of the prothorax are

22 15. suspended in a m_embrane and are not closely associated with the remainder of the thorax. - The tibia (ti) bears on its ventral surface a row of stiff hairs corresponding to the eye brush in the honey bee. On the distal and of the tibia and the b ase of the first tarsal joint is a stru9ture known as the antenna cleaner (~ )shown enlarged in figure 19. It consists of a crescent shaped notch in the base of the tarsus, bearing a row of short stiff teeth, and a large flat spine borne by the tibia. This spine also has a row of minute teeth on its distal half. By drawing the antenna through this organ the bee is able to remove any pollen or other foreign matter adhering to it. The first tarsal joint also bears a brush of long, stiff hair1hsed for cleaning pollen from the body. The mesothoracic legs (fig. 20) are quite fir.mly articulated v:ith the body wall, so that comparatively little movement of the coxa is possible. '::he femur bears on the ventral surface near the proximal end a brush of short stiff hairs. The tibia is clothed v lith plu.mose hairs except for an area ~ which is apposed to the femur when the leg is flexed. It bears at its distal end a long, serrate spine (tis). snodgrass (1925) calls this structure in the honey bee the wax pick, but as Halictus lerouxi does not secrete wax, its function here is doubtful. The first tar_sal joint is long, and thickly invested with long plumose hairs. ~t the distal end of each tarsal joint is a ring of long, spine-like hairs. The metathoraaic legs are allo~ed a somewhat wider ra1~e

23 16. of motion than are the middle lega, due to the fact that they are bounded poster iorly by the v~eakly-chi t inized propodeal sternum and by the membrane connecting the thorax with the abdomen. These legs form the principal organs for carrying pollen, and are consequently very thickly supplied with hairs. The pollen carrying baskets (fig. 2l~pb) are located on the femur. They consist of a mass of hairs arising from the dorsal and ventral surfaces of the femur, curving posteriorly and the free ends of the two masses intertwining. This forms a tube~like structure in which the pollen is placed for transportation. The tibia is entirely covered with long hairs which are directed postero-dorsally On the distal end are borne two spines, projecting ven trally. The posterior one has a finely serrate edge, while the inner one bears nine blunt teeth (fig. 22), those at the base being quite large and diminishing in size progressively until those at the outer end are more like small knobs. There is also a small knob-like projection on the dorsal side of the tibia at its distal end. The long first tarsal joint is thickly clothed with long hairs_, and at the distal end, on the dorsal margin, there is a flat structure formed of stiff spines growing closely together. The remaining tarsal segments, as in the other legs, bear several long hairs. The legs of the male are very similar to those of the female, except that they are not as thickly clothed with hairs. The metathoracic legs do not bear pollen baskets, and both of the tibial spines are finely serrate. The flat

24 17. structure on the end of the first tarsal segment of the metathoracic leg is not present in the male. The ultimate segment of the tarsus is practioally the same in all legs of both sexes. It is somewhat longer than the other segments, except the first, and bears at its apex two articulated claws, ~ the ungues. These claws are large dentate o~gans (fig. 23, 24, 34), flaring outward and downward. The outer tooth is longer than the inner. They are articulated with the unguifer (ung) on the apex of the segment by a small knob. Each claw bears on its under surface two long, stiff hairs. Underneath the unguifer there is a flat plate, the unguitractor {ugt), which Crampton (1923 a) considers may represent a rudimentary tarsal segment. B.stween this and the base of the claw on each side is a small, pad-like structure, the pulvillus (~). Arising ~etween the bases of the claws is an organ consisting of a basal stalk with a flat, pad-like appendage. This is the arolium {~),by means of which the bee is able to cling to smooth surfaces. The terminal part is bi-lobed, but the two lobes are ordinarily folded together. There are two chitinized bands in this structure. The stalk is clothed with hairs and bears dorsally on each side a long spine, which in the honey bee, accordli1g to Snodgrass (1925), serve to help fold the two lobes of the arolium together when the nature of the surface on which t}le.inseot is walking makes it unnecessary that the structure be used for clinging. 4. Endothorax. Each thoracic segment bears a large

25 18. internal furca for the strengthening of the wall and for the attachment of muscles. The furca of the prothorax is shown in dorsal and caudal views in figures 30 and 31. It arises from the pit which appears externally in the mid-ventral line (fig. 26, rfl), and forks int.o two triangular plates. These extend up to meet the pleural apophy~es and inward to meet each other on the median line, forming a broad, shield-shaped plate (fig. 30, fl) This plate has a thin keel. (fig. 31, K) extenfing above and below at right angles to it at the line of fusion. The furcae of the meso - and metathoraces are fused to form a single large internal structure (figs. 27, 28, 29). The mesothoracic furca has two roots (fig. 26, rf 2 ) giving Iis e to a median lgngitudinal plate which forks laterally. T~ese lateral brinches are then joined for a short distance by the branches of the metathoracic furca, which is a narrower plate ha'iing only one root. After fusing for a short distance they separate again, making two insertions on the body wall on each side, each on the pleuron of its own segment. ~he furcae are connected by a bar at the points of first furcation (fig. 29, b). This bar extends laterally from the metafurca and ia inserted on a broad plate which covers the mesocoxa. It is joined by a chitinous plate with the median portion of the metafurca. The points where the lateral arms of each furca are fused with those of the other are connected by a broad chitinous plate (I!).

26 19. C. Abdomen. 1. General Structure. The abdomen of Halictus lerouxi consists of nine segments of which the first forms the propodeum of the thorax. In the female the eighth and ninth are normally invaginated within the seventh, so that there are only six segments visible in the abdomen proper. In the male only the ninth is hidden, so that there are seven visible segments besides the propodeum. A membranous tubular structure bearing the anus at its tip (fig. 42 X T), which corresponds to the tenth abdominal segment of the honey bee (Snodgrass, 1925) is present in the female. abdomen is loosely articulated with the propodeum by means The of a narro\-j stalk and a membranous union, so that it is freely and independently movable. a. Each abdominal segment consists of a tergal and,. sternal plate. The tergal. plates cover the dorsal and lateral parts of the segments, and their edges overlap those of the sterna. Each plate covers the one behind by a wide margin, and they are connected by an intersegmental membrane. (figs. 42, 43, 54, im). Each tergal plate is connected with the corresponding sternum by a pleural membrane which is entirely concealed. The eternal plates (fig. 54) are broader than long, and each anterior angle has a broad process bearing a short lateral arm. Between these two processes is the intersegmental membrane which connects the plate with the one next in front. The membrane is inserted on the dorsal surface of the next plate near the hinder margin. structures are similar in both male and female.

27 Genital Structures. a. Female (Sting). The genital structures in the female have been greatly modified to form a sting. The sting, with the eighth, ninth and tenth abdominal segments, is concealed in the sting chamber formed by the sixth and seventh segments {fig. 42), from which the whole structure is suspended by membranes. The sti~g consists of a long. pointed shaft, slightly curved upward and directed posteriorly. It is swollen towards the base into a bulb-like structure (sb} which is open below by a median cleft (fig. 46 me). The base of the sting is closely associated with three pairs of plates. These are the quadrate plates (IX T), the triangular plates (VIII~), and the oblong plates (IX S). They correspond to the ninth tergum and the eighth and ninth sterna respectively, and form the mechanism by which the sting is protruded when it is to be used. The structure of the sting is aeen in cross-section in figure 47. It consists of three hollow outgrowths of the body wall, one dorsal and two ventral. Each of the ventral structures (lancets, lot) is connected Vii th the dorsal one (sheath, sh) by a tongue-and-groove joint which allows longitudinal movement of the parts while at the same time forming a strong union. Each of these three structures contains a prolongation of the body cavity {be) and the three form a tube (po) through which the poison flows v:hen the sting is used. In front of the bulb of the sting two arms extend dorsally (figs. 42, 46). These are each double, consisting of the base of the lancet (lcta)and an arm from the sheath (sha).

28 21. The lancet arm articulates with the triangular plate (VIII 2) and the sheath arm v;ith the oblong plate (!! ~). There is another structure (fig. 48, ~) shaped like the breast bone of a chicke n v1hich articule.tes with the base of the sheath bulb and curves posteriorly over it. This is an apodeme for the attachment of muscles, probably the retractor muscles of the sting. Each oblong plate bears posteriorly a sting palp (figs. 42, 46, 56, splp} which normally overlaps the sides of the sheath bulb. The ventral posterior angle of the triangular plate articulates Tiith a knob on the dorsal margin of the oblong plate. The dorsal posterior angle of the triangular plate articulates with the large quadrate plate,which overlaps the oblong plate and is in turn overlapped by the eighth tergum. The points of articulation of the triangular plate are shown in figures 42 and 46. Snodgrass (1925) homologizes the parts of the sting of the honey bee as follows: The lancets correspond to the ventral valvulae, arising from the eighth segment; the sheath is formed from the united inner valvulae of the ninth segment; and the sting palps are formed from the d9rsal valvulae. This makes the triangular plate equivalent to the eighth sternum, and the oblong plate to the ninth sternum. The sting of H. lerouxi closely resembles that of the honey bee, and these homologies may be accepted for it. The eighth tergum is represented by the large spiracle-bearing plates (fig. 42, VIII T). The quadrate plates are the lateral parts of the ninth tergum, the dorsal part having disappea.red. The tenth segment is

29 22. represented by the small membranous structure bearing the anus at ita tip. The lancets of the sting of H. lerouxi, unlike those of the honey bee, are not barbed, hence the weapon may be used repeatedly. b. IIale. The male genital organs, like those of the female, are hidden in the posterior end of the abdomen {tigs. 43, 51), in a chamber formed by the terga of the seventh and eighth, and the sternum of the seventh, segments. The sterna of the eighth and ninth, and the tergum of the ninth, segments are hidden. The seventh and eigh-th spiracles are concealed by the tergum of the next preceding segmeht (fig. 51). The eighth sternum (fig. 44) is a very narrow transverse band connected with the seventh by a membrane (fig. 43, im). appears to be folded upon itself, the ljwer part of the fold bearing at the canter a short, blunt, backward-projecting structure covered with short hairs. The ninth tergum. (fig. 55, IX!) is in two parts, one on either side of the body and - shaped like an inverted u. The anus (~) opens above the connected by the tenth tergum (X T) the whole structure being tenth tergum. The ninth sternum (fig. 53) has had its lateral extremities produced upward until they meet on the mid-dorsal line. It carries the two pairs of claspers, a large outer pair (figs. 43, 49, 50, oclsp) and a smaller inner pair ( iclsp). These claspers are directed ventrad, and are shown in medial view in figures 46 and 52. It There is another small, somewhat pointed structure attached to the basal part of each inner claaper (fig. 49, ~J

30 23. Henneguy (-1904) quote-s Dufour concerning the copulatory ~ apparatus of the male.bumble-bee as follows:- "The copulatory armor of bumble-bees comprises: a basal piece, median and below, on which is inserteaja pair of strong, moveable, hooked appendages, shaped like a pair of tongs, and constituting a prehensile organ, the :forceps; lower and a little behind this tongs, is found the volaelle, formed by a second pair of less ' - solid appendages, and carrying at their extremities a moveable, trowel-shaped piece; between these parts and the penis is tbe found~hypotome, made up of a pair of lamellar appendages, spoon-shaped and borne on a median piece; lastly.the sheath of the penis, situated in the canter of this complex apparatus, is furnished above v:ith a horny, lanceolate blade, and bears on each side a rigid rod ~hich terminates in a hook." Henneguy goes on further to say, in speaking of the pneumophyses of the honey bee: "This peculiarity {the pneumophyaes) which ~xiats known to Swammerdam " If the above interp~etation in no other insect, was already is applied to the copulatory organs of the male R lerouxi, the outer claspers apparently are the l!forceps" (figs. 49, 50, ocls;e); the inner claspers form the "volsella" {iclsp); and the structures attached to their bases form the hypotome (h). The outer claspers are quite large, and articulate both dorsally and ventrally with the ninth sternum, their bases meeting on the median line. moveme_nt of the organ. This allows moderate lateral The actual clasping part is borne distally, and is furnished with a row of long hairs. '.rhe

31 24. inner claspers do not articulate directly v.'i th the ninth sternum, but by means of a long process with the dorsal angles of the bases of the outer claspers near their poin~s of articulation with the ninth sternum. The inner clasper is quite strongly decurved, and bears a quite sharp point.

32 25. III. INTERNAL ANAT0It1Y A Digestive System. 1. Digestive Tract. The digestive tract in Halictus lerouxi, as in other insects,. may be divided into fore-, mid- and hind - intestine. 1the fo're-intestine consists of pharynx, oesophagus, honey-stomach, and proventriculus; the mid-intestine~onsists of ventriculus; and the hindintestine consists of the ilium with the 1~lpighian tubules, and the reotum {fig. 59). The pharynx (~) extends from the mouth opening to about the middle of the head. It is a quite large structure with a chitinous rod along each side (phr). Henneguy (1904} and Snodgraseft 1925) both describe the pharynx as a suctorial organ enabling the bee to imbibe nectar. Jehind the pharynx is the oesophagus (!!}, a narrow tube extending through the thorax into the first segment of the abdomen. Just before leaving the head through the occipital foramen, there is a slight enlargement of the oesophagus v;i th glands in its walls ( ogl). This structure is described by ~-=enneguy (1904} but no name is given to it. He mentions it particularly as being present in insects which are deprived of salivary glands, but these latter structures also are present in lerouxi, as will be described later. Snodgrass does not sh0\'1 the presence of this oesophageal gland in the honey bee. In the first segment of the abdomen the oesophagus expands into the large, thin-walled honey-stomach or crop, where nectar is stored for transportation.

33 26. The proventriculus (!) is much smaller in diameter than is the crop, and it is quite short. It extends into the crop as a neck-like stalk, and acts as a valve in passing food to the stomach. The ventriculus or true stomach (!) is a stout, thick-walled tube which forms a coil upon itself. The walls have a large number of constrictions on the outer surface, giving the organ a segmented appearance. Toward the posterior end the ventriculus becomes somewhat narrowed. The ilium or small in_testine (si) is a narrow section of the digestive tract, slightly swollen in the middle, and bearing the Halpiphia.n tubules at ita anterior end. It connects the ventriculus -r1i th the rectum. The lialpiphian tubules (~) number about tv;enty-four, varying slightly in different individuals. Each is a long, coiled tube opening separately into the anterior end of the small intestine. They are coiled almost inextricably about each ot.her and about the viscera of the abdomen. The rectum (!:) is larger in diameter than the ilium, and is slightly constricted in the canter. The anterior portion bears on its surface six reatal glands {~) The posterior part opens externally through the anus. 2. Glands. Bordas (1895a) describes eight pairs of salivary glands in conneation with the digestive tract, but only seven of these were found in Haliotus lerouxi. They are shown in figure 59. The ducts could not be followed, owing to poorly preserved material.

34 27. Gland number I is the thoracic gland. It is made up of many small glands opening eventually into a common duct, and lies in the anterior pa_rt of the thorax. The second pair of' glands (g) i.s very small and lies behind the brain more or less underneath the oesophagus. They are known as the protocerebra.l glands. The supracerebral glands (l!!) lie over the pharynx and above and in front of the supraoesophageal ganglion. Figure 59 represents them as lying some distance apart so as not to hide other structures, but in reality theulie close together. The lateropbaryngeal glands (IV) are quite small and lie close on either side of the pharynx between it and the anterior arms ot the tentorium. The mandibular glands (!) lie against the genae just at the bases of the mandibles. They are quite small. ~he largest glands in the head are the interno-mandibular.(vn,they lie between the mandibular glands and the anterior ends of the tentorial arms. The suprapharyngeal glands (VII} are small glands lying above the pharynx in front of the supracerebral glands. B. Nervous System. Due to poor preservation of material it was found impossible to study the nervous system in detail. The general appearance of the central nervous system is shown in figure 60, vjith an enlarged view of the brain in figure 61. The nerves to the various parts of the head, except the antennae, oould not be followed. The nervous system consists of the brain and a ventral chain of six ganglia; connected by commissures. The brain

35 28. (fig. 61) is a bilaterally symmetr-ical structure, each half consisting of three lobes, the fore-brain {br), the - - all broadly joined. optic lobe (ol), and the antennal lobe (al). These are The fore-brain or'protocerebrum is the largest lobe of the brain and bears the three ocelli. Just beneath the median ocellus is an opening (! ) through which a trachea passes. The optic lobes are borne laterally on the broad optic nerves (~),and are about the size of the compound eyes. The antennal lobes or deutocerebrum are smaller, and give rise to the nerves which innervate the antennae. Underneath the protocerebral lobes is given off on each side of the pharynx a broad nerve, the curcumoesophageal commissure. These connect the brain with the suboesophageal ganglion {soeg) and surround a small opening through which the pharynx passes. From the posterior end of the suboesophageal ganglion are given off ttio commissures which pass backward through the neck to the first thoracic ganglion. prothorax surrounded by the prothoracic furoa. This lies in the It gives off three pairs of primary nerves, the posterior of which forks, one branch going to innervate the legs. The second ganglion is very large, and is surrounded by the meso - and metathoracic furcae. Since it innervates not only the two thoracic segments, but the propodeum and first abdominal segment as well, it is apparently a compos ita of all fo ur ganglia. The nerves to the first abdominal segment may be seen arising close to the

36 29. longitudinal oommie~res and fol~owing them back through '"'"' the peti_ole to the fir.st segment. Other nerves given off more anteriorly innervate the thoracic structures. The first abdominal ganglion lies in the first but innervates the second segment. The next thr.ee lie in t_he third, fourth and fifth segments, each innervating the segment which contains it. The laat also innervates all the structures behind it, so that it is apparently a composite. ganglion formed from the fusion of the ganglia properly belonging to the sixth, seventh, eighth, ni11th and tenth segments. This condition differs from that found in the honey bee in that the latt.er has five abdominal ganglia, th~ast supplying only the seventh, eighth, ninth and tenth segme.nts, and lying in the s-eventh segment. c. Reproductive System. 1. Hale. The reproductive system in Halictus ler9uxi resembles fairly closely that found in the honey bee. In the male (fig. 57) it consists of testes, vasa deferentia, accessory glands, ejaculatory duct, and penis. The testes have become united to form a single, somewhat quadrangular body (tes) which lies on the dorsal side of the digestive tract. This body is connected on each side of the proventriculus of the intestine by a short vas deferens (~} with the accessory glands ( acgl). One of these lies on each side of the body. They are more or less ovoid in shape and each has a large duct of about the same length as the gland itself. These two ducts meet at the base of the ejaculatory duct (ejd) and this latter leads through the circular ninth sternum to the penis (pb.). The penis is a large, bulb-sha:ped structure attached externally between

37 30. the inner claspers. snodgrass (1925) and others deacri~e the pe.nis proper as being invaginated into this bulb in the honey-bee, being everted at the time of.mating. This condition probably holds in H. lerouxi also, although it was not possible to demonstrate it. 2. Female. ~he female reproductive system consists of ovaries, oviducts~ vagina, spermatheca and spermathecal gland, accessory gland, and bursa copulatrix (fig. 58). The ovaries (!) are long, narrow structures, each made up of three ovarioles. They pass dorsal of the intestine, one on each side of the proventriculus, arid the ends are united to form a common suspensory ligament. The lower ends of the ovaries empty into the oviducts (od} and these in turn unite just before entering the vagina (!) The vagina is a large, membranous sac dorsad of the base of the sting and attached late~ally to the ninth tergum. The spermatheca (~) is borne on the dorsal side of the vagina, being connected with it by a short duct. It is a small, spherical body, slightly constricted where the spermathecal gland is borne on its surface. This gland is shaped like a divided hook, the sperma theca being between the two ha..lves of the hook. opens into the spermathecal duct at the same place as does the spermatheca. The accessory gland is a large, divided gland, ~ one arm being shorter than the other {aogl), It In normal position it lies close to the digestive tract, and is curved to fit over the ventriculus. From its point of entry on the wall of the burs-a QOpulatrix this gland may possibly be homologous with the alkaline gland in the. sting of the honey bee, a structure which

38 31. could not be found in H. lerouxi. The bursa copulatiix is not clearly differentiated from the vagina in H. lerouxi, but may be considered to be the perpendicular terminal portion of this structure. comstock (1925) states that ".a bursa copulatrix is said to be wanting in Hymenoptera ", but as it has been described in the honey bee, as well as other species, it is in all probability present. The vulva is a transverse opening in the intersegmental membrane between the seventh and eighth sterna just in front of the base of the sting.

39 32. Both the external and internal anatomy of Haliotua lerouxi are discussed in this paper. Unfortunately the study of the internal anatomy could not be completed, due to poor material. The structures.throughout are compared with those found in the honey bee, the "Anatomy and Physiology of the Honey Bee", by Snodgrass (1925), being used exte1~ively,..._i; as a reference for this purpose. The head of R. lerouxi bears all the structures found in other representatives of the higher Hymenoptera. The mandibles are present as strong biting jaws. The maxillae and labium are elongated to form a proboscis which is suspended in a membrane from the under side of the head. The lacinia of the maxilla is apparently absent. The antennae show sexual differences, that of the male being considerably longer than that of the female and having twelve segments in the flagellum,as compared v.'ith eleven in the female. The tentorium of H. lerouxi differs from that of the honey bee in bearing a pair of dorsal arms which are inserted near the bases of the antennae. The anterior and posterior arms of one side are united y,;i th those of the other by a V-shaped lamella, the apex of which is in turn united v]ith the median line of the ventral head wall by another thin lamella. The thorax, as in all of the higher Hymenoptera, has a prop«)ldewn as well as the three true thoracic segments. The prothoracic pleura-sternum is attached to the remainder

40 33. of the thorax only by a membrane. ~he remaining parts of the thorax form a compact structure. The postscutellum of the mesothorax is borne internally, and extends back into the propodeum. The wings of each side are synchronized during flight by a row of hamuli borne on the anterior margin o1 the hind ning. The venation of the hind wing differs from that of A. 1:ellifica in having an additional vein, apparently 111, present. The legs have developed various accessory structures ~or use in pollen collecting and in cleaning the various parts of the body. Each thoracic segment bears an internal furca for strengthening and for muscle attachment, those of the meso - and meta- thoraces being united to form a single structure. The abdomen consists of nine complete segments, pl~e a rudimentary tenth. The first segment forms the propodeum of the thoracic region. The genital segments are invaginated into the posterior end of the abdomen. In the female the external genitalia have been modified to form a sting consisting of two lancets supported by a sheath, and a pair of palps. The terminal abdominal segments also are modified. In the male the genitalia consist of tbo pairs of claspers, a structure known as the hypostome, and a penis. The digestive tract is similar to that of A. 1iellifica. It bears near the anterior end of the oesophagus an enlarge~ ment containing glands in its walls, a structure not borne in the honey bee. Tllere are seven pairs of salivary glands. The Malpighian tubulee are about twenty-four in number, each opening separately into the ilium. The rectum has six rectal glands.

41 34. The nervous system was not studied completely, due to poor material. It differs from that of the honey bee in having only four abdominal ganglia. The reproductive system of the male consists of the usual parts, except the seminal vesicle, v;hich is undifferentiated from the vas deferens. The testes are fused in the median line to form a single body. The structure of the penis could not be determined, as it was found impossible to evert it. The female reproductive s:rstem is normal in its make-up. Each ovary consists of three ovariolea. The accessory gland is enormously enlarged, and may correspond to the alkaline gland of the sting in the honey bee, a structure v:hich could not be demonstrated in H. lerouxi.

42 35. v. Acknowledgements. The writer v,;ishes to express his thanks to Dr. E.M:. DuPorte for his assistance in homologizing structures and for his criticism of the paper; to Dr. -:::.H. Brittain for many helpful suggestions as to methods of study, etc.; and ",~.~hi tehead for suggestions as to technique, and for his aid in the preparation and photographing of the plates. Thanks are also due the library staff for their willingness in using the inter-library loan service to obtain references not in the library.

43 36. VI. Bibliography. Baird, A.B., Some notes on the female reproductive organs in the Hymenoptera. Proc. Acad. Ent. Soc. 7: Bishop, G.R., Fertilization in the honey bee. liale sexual organs. Jour. Exp. -zoo1. 31: Bishop, G.H., 1920 a. Fertilization in the honey bee. Disposal of the sexual fluids in the organs of the female. Jour. ~ zoo1. 31: Bordas, M.L., Apparei1 glandulaire des Hymenopteres..ann. Soc. Jat. zool. 19: 1~ Borde.s, :r..r. L, 1895a. Appareil genital male des Hymenopteres. Ann. Soc. Nat. zool. 20: Brittain, W.H., Report on orchard pollination studies (unpublished). Brittain, w.n., Report on orchard pollination studies (unpublished). Cheshire, F.R., The apparatus for differentiating the sexes in bees and wasps. Jour. Ro~Mi! Soc. ser. II, vol V: l-l5. Comstoek, J.H., "~he Wings of Insecta", PP xviii + 430; 427 figs. Ithaca, N.Y. Comstock, J.H., "An Introduction to Entomology 11 pp.xix ; 1228 figs. rtha ea, n y.

44 37. Comatock, J.E. and Kellog, v. L., "The Elements of Insect Ana.tomyn. pp. 145; 11 figs., Ithaca, II.Y. Cook, ~.J., "The Beekeeper's Guide", PP xi+ 543; 295 figa., Ohicago, Ill. Cowan, T. ij r., "The Honey Bee. Its I~ a tura.l History, Anatomy and Physiology". pp. xii + 220; 73 figs. London, Eng. Crampton, G.c., The sclerites of the head, and the mouthparts of certain immature and adult insects. Ann. Ent. Soc. Amer. 14; Orampton, G.c., A phylogenetic comparison of the maxillae throughout the orders of insects. Jour. ;._;.Y. Ent. Soc. 31: Orampton, G.c., 1923 a. Preliminary notes on the terminology applied to the parts of an insect's leg. can. Ent. 60: Henneguy, L.F., "Lea Insectes (l:orphology, Reproduction, Embr~:rogenie} ". pp. vii + 804; 722 figs; 4 pl. Paris. Imms, A.D., "A General textboo k of Entomology." pp. x + 698; 607 figs., Uew York, lt. Y. MaoGillivra.y,.t~.n., The lacinia in the maxilla of the Hymenoptera. Ann. Ent. Soc. Amer. 5: Rohwer, s.a., and A.B. Gahan, Horismology of the hymenopterous wing. Proc. Ent. Soc. ~.;ash. 18:

45 39. Snodgrass, R.E., '!'he thorax of -insects and the articulation of the wings. Proc. u.s. Nat. Mus. 37: 511~ S_nodgrass, R.E., The anatomy of the honey bee. U-~ ~! Bur. Ent. Tech. Bul. 18. Snodg_rass, R.. E., The thorax of the Hymenoptera. Pro c U. S I-f at I~Ius 3 9 ; Sno4grasa, R.E., "Anatomy and Physiology of the Honey Bee." PP xv + 327; 108 ~i ~T y k ";IT y.j.. gs.,.:.., ew or, -~. Snodgrass, R.E., Iorphology and mechanism of the insect thorax. Mise. Coll. 80, ITo. 1. Snodgrass, ~.=., Smithsonian!1orphology and evolution of the insect head and its appendages. Smithsonian ~Iisc. Snodgrass, ~. E., Cell. 81, J:lo.3. ITorphology of the insect abdomen. Part I. General structure of the abdomen and its appendages. Cell. 85, r:o. 6. Smiths onian = :isc.

46 FiP. A. Larva of II. craterus : E. Pupa of ~ craterus G. Adult of H. oraterus D. Larva on pollen pellet E. Entrance to nest F. Section through nest G. Section through nest Explanation of Plate I. (From Brittnin,l930)

47 ... -

48 Explanation of Plate II (Magnifications approximate}. Fig l!'acial vievj of head (l:ale} Caudal " " " Lateral " " " 1/ra.ndible (I.:ale) x 87. Proboscis (liale) x 20. " " X 20. X 20. X Tip of proboscis (1:Iale) dorsal view x Cross-section of proboscis near canter x 87. abbreviations used. ant antenna ati anterior tentorial invagination c cl e ea es f -- fcs fp g ga gl hvb: cardo clypeus compound eye arms of epicranial suture stem of epicranial suture frons fronto-clypeal suture frontal plate gena galea glossa h~rpopharynx 1 labrum lb labium lr lprum

49 lplp labial palp 0 occiput oc ocelli of occipital foramen pg post gena pg~l po pos pti paraglossa postocciput postoccipital suture posterior tentorial invagination rl,r2 - chitinous rods in membrane of proboaois s atipes t tentorium

50 .:... u... e -. --mrplp 4

51 Explanation of Plate III (Magnifications approximate). Fig. e. 9. Tip of maxilla (male) dorso-lateral view :x 57. Glossa, ventral view x Proboscis (male) side view, parts sprea4 x 20. Base of proboscis from behind x Labrum - epipharynx, ventral view 13. antenna of male x Antenna of female x Saggital section of head x ~entorium, dorsal view x 40. aa ant bt c cl da e endg eph 'xg f fp ga gl hph.. Abbreviations used. Anterior arm of tentorium antenna -- body of tentorium oardo olypeus dor-sal arm of tentorium compound eye endogalea epipharynx exogalea frons frontal plate galea glossa -- -~ypopharynx 1 labrum la V-shaped lamella of tentorium.

52 lp1p lr labial palp lorum md mandible mt mentum mxplp - maxlllary palp oc ocelli of occipital foramen pa pgl ph :phr posterior arm of tentorium paraglossa pharynx :pharyngeal rod rl ' r2 - chitinous rods in membrane. of proboecie. s -- stipes

53 lut pill:' ph,, dd..,, '' ' r --- ~-~- ~~~;:====~ 15 mt 14 9 t

54 Explanation of Plate IV (Hagnifioations approximate). Fig Lateral view of thorax x 30. 2ore-leg (female) x 20. i:..ntenna cleaner x 43. I.:iddle leg (female) x 20. Hind leg (female) x Tibial spine of hind leg (female) x Tarsal claws, do~sal view x Tarsal claws lateral view x 87. ~bbreviations a hairless area of tibia. ao antenna cleaner aob antecoxal bridge anp anterior notal wing process ar arolium axe axillary cord c coxa cs cervical sclerites epm epimeron eps episternum fe femur fu furrow of mesothorax 1 base of leg metn - metano turn pb pollen basket pnp ps posterior notal wing process pleural suture. used.

55 pu pulvillus s souto-scutellar suture se scutum sctl - soutell'wil sp spiraole IT 1st abdominal targite ta tarsus tac tarsal claw tgl tegula ti tibia tis tibial spine tr trochanter u ungtlis ung unguifer ugt ungui tractor w wing of pronotum wp pleural YJing process.

56 ... l I

57 Explanation of Plate V (ltagnif1.oations approximate). Fig. 25. Dorsal view of thorax x Ventral view of thorax x Furca of meso and meta-tho%8ces, dorsal view x Caudal view of endothorax x 20. aob antecoxal bridge. Abbreviations used. ru1p anterior notel wing process 01, 2 & 3 - coxae. cc coxal condyle cs cervical sclerites epm epimeron eps episternum f2 furoa of mesothorax f3 furca of metathorax fu furrow of mesothorax metn pa pph ps psp metanotum parapsides prephragma pleural suture pleuro-sternal plate rf 1, 2 & 3 -- furcal roots,. s -- scuto-scutellar suture s 1 & 3 -- pro-and meta-thoracic ls 1st abdominal sternum sterna se -- scutum sctl - soute11um T 1, 2 &' 3 -- thoracic terga IT 1st abdominal tergum Vs, Vs2 -- secondary scutal sutures.

58 27 2S 28 26

59 Explanation of Plate VI (Magnifications approximate). Fig Furcae of meso- and meta-thoraces, lateral view x 20. Furoa of prothorax, dorsal view x 40. Furca of prothorax, caudal view, x 40. Tergum of mesothorax x 20. ]1Iandible of female, postero-meeal view, x 43. Tarsal claws, ventral view x 87. Front v.'ing x 10. Axillary aolerites of front wing x 87. Hind wing x 10. ao anp ar axe b 00 os eps f. 1 k m pnp poph pph pso 38. Axillary soleritea of hind wing x 87. Abbreviations used. acetabulum anterior notal ~ing process arolium axillary cord bar of furcae condyle cervical scleritea episternum furca of prothorax keel of fur ea media pleural apophyses posterior notal ning process postphragma prephragma postscute llu.m

60 pu pulvillus R Se radius scale of sub-costa sot - scutum actl - scutellum t tooth of mandible u unguis ugt - unguitractor ~ secondary sclerite of poataoutellum y secondary axillary aclerite 1, 2, 3, 4 -- axillary sclerites.

61 1 t 'TT-..._

62 Explanation of Plate VII (Haenifications approximate) ~,ig. 39. Abdomen (female) lateral view X ' 41. n " ventral '' X 10. " dorsal " X Sting chamber from left side X Jale genitalia in normal position, left side x 43. 8th sternum of mala, ventral view x Inner clasper of male, mesal view x Sting and poison apparatus, ventral view x 30. Abbreviations used. IT-IX ~ -- abdominal terga IlS-IX S - abdominal sterna VIII S 8th abdominal sternum or triangular plate (figs. 42 & 46). IX T 9th abdominal tergum or quadrate plate IX S (figa. 42 & 46~. 9th abdominal sternum or oblong plate (figs. 42 & 46). a anus ialsp--inner clasper im let intersegmental membrane lancet of sting lcta - arm of lancet me median cleft of bulb of sting oclsp - outer clasper pgl -- poison gland pgld - poison duot ps poison sac sb bulb of sting

63 eh -- sheath of sting sha arm of sheath sp spiracle splp - sting palp.

64 J.l 39 -lis --'"X -VIJls ~- --let a, sha "" sb 42 44

65 Explanation of Plate VIII (Magnifications approximate). Fig Cross-section of sting near middle x 74. Anterior view of base of sting, showing apodeme x 40 rale genital structures, ventral view x 43. Male genital structures, dorsal view x 43. Tip of male abdomen, lateral view x 20. Outer clasper of male, mesal view x 3~. 9th sternum of male, posterior view x th sternum of male, dorsal view x th and lo,th terga of male x Stin~ palpus, lateral view x 21. Abbreviations used. VI T - X T -- a.bdominal terga VI S - IX S - abdominal sterna a ap bo h anus apodeme body cavity hypotome iclsp -- inner clasper im intersegmental membrane let lancet of sting lcta - arm of lancet oclsp -- outer clasper p pc ab penis poison canal bulb of sting sh sp sheath of sting spiracle.

66 fijit ss Sl -I 55 S2 -- c -pc ~be 47 ' C se ash

67 Explanation of Plate IX (Magnifications approximate). :B,ig Hale reproductive system x 40 Female " n x 20 Digestive system x 10. Nervous system x Brain, anterior view x 21. Abbreviations used. I - VII salivary glands IG - VI G - ga1~lia of central nervous system acgl accessory gland al antennal lobe of brain an antennal nerve ap apodeme br protocerebral lobe of brain a compound eye ejd ejaculatory duct hs honey stomach m o od oes ogl ol on ov pb pgl ph M:alpighian tubules ocelli oviduct oesophagus oesophageal gland optic lobe of brain optic nerve ovary bulb of penis poison gland pharynx

68 phr pharyngeal rod ps poison sac pv proventriculus r rectum rg rectal gland s spermatheca sd spermatheoal duot sg spermathecal gland si small intestine soeg - suboesophageal ganglion tea testes tp passage for trachea through brain v vagina vd vas deferens vt ventriculus.

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