DASl'POGONINAB 



ROBBER FLIES OF THE WORLD 



211 



convex and retreating below. Eye wide, strongly flat- 

 tened in front, it is of medium length, a little more 

 prominent on the lower half ; it is nearly plane through- 

 out the middle of the posterior profile but convex and 

 recessive above and below. The occiput is almost ob- 

 literated in profile but appears as a thin border along 

 the posterior margin of the eye at the vertex. The pile 

 of the occiput is reduced, on the ventral portion, to 

 a very few fine hairs which though very slender are 

 bristly in character and proclinate; dorsally there is a 

 single row of similar, slightly curved hairs which at 

 the vertex are perhaps a little more stout. The pro- 

 boscis is small, slender, with nearly parallel sides ; from 

 the dorsal view the apical third is a little tapered, from 

 the lateral aspect it is plane ventrally and rounded 

 dorsally to a blunt apex. There is a thin, low, medial 

 ridge. At the apex are slender hairs and 2 or 3 pairs 

 of long, slender bristly hairs arise basally at the middle. 

 Proboscis directed obliquely downward; its length is 

 equal the length of the eye. Palpus small, clearly of 

 two segments ; the first segment more robust, excavated, 

 and with 2 or 3 bristly hairs ventrally and basally and 

 4 others ventrally and apically; the second segment 

 set at a slight angle, cylindrical, slightly curved down- 

 ward with truncate porate apex and 2 long, slender 

 bristles ventrally at the apex. 



The antenna is attached at the middle of the head ; the 

 first two segments are quite short, of nearly equal length, 

 second segment considerably wider distally, third seg- 

 ment elongate and slender and beadlike or bulblike at its 

 base, where it is considerably narrower than the second 

 segment or even the first segment. The third segment is 

 strongly attenuate distally and carries a rather stout 

 style as long as itself ; this style is slightly bent, curved, 

 and bears 5 or 6 long, slender, dorsal plumes, a like 

 number of lateral, and at least 7 or 8 ventral plumes, 

 besides several at the apex. First segment with 2 long, 

 fine hairs ventrally, 2 shorter ones dorsally, the second 

 segment with a long, slender bristle ventrally and short 

 hairs apically above. 



Head, anterior aspect : The head is nearly two times 

 as wide as high. Face below antenna less than a third 

 the head width, with parallel sides, the vertex slightly 

 widened. Subepistomal area large, oblique, plane, bare, 

 and a little longer than the face. Face densely and 

 minutely micropubescent, with a cluster of long, fine, 

 bristly hairs in the middle of the lower half of the face 

 and with 3 pairs of similar bristly hairs on the upper 

 lateral margin of the epistoma. Vertex very little ex- 

 cavated with gently sloping sides, slightly widened. 

 The large, wide, rather high ocellarium bears large 

 ocelli ; its sides are nearly vertical and carry a pair of 

 quite long, divergent, moderately stout, anteriorly 

 directed bristles which are as long as the whole third 

 antennal segment; they are attached between the pos- 

 terior ocelli and along the anterior and posterior margin 

 of each posterior ocelli is a single, short, bristly hair. 

 Dorsally the vertex is excavated and flared postero- 

 laterally. Anterior eye facets greatly enlarged. 



Thorax: The thorax is almost everywhere densely, 

 minutely pubescent ; a few bare areas tend to appear, 

 due apparently to rubbing. Mesonotum almost equally 

 abrupt and convex posteriorly as anteriorly. Pile of 

 mesonotum very scanty, consisting of long, nearly erect, 

 bristly hair. There is a band of such acrostical pile 

 anteriorly and also in front of the suture 4 or 5 mod- 

 erately long, slender, dorsocentral bristly hairs which 

 become a little longer posteriorly behind the suture. 

 Humerus micropubescent only. The following com- 

 plement of long, pale, moderately stout, lateral bristles 

 is present: 2 notopleural, 1 postsupraalar, 1 postalar, 

 and 1 pair of scutellar bristles. Scutellum thick, con- 

 vex and pubescent; the disc has on each side 4 or 5 

 slender, long, fine hairs. Propleuron with a tuft of 

 stiff, bristly pile ventrally; anterior collar with 5 or 6 

 pairs of quite long, bristly hairs; posterolateral pro- 

 notum with 7 or 8 long, slender, bristly hairs; upper 

 anterior mesopleuron with a band of 7 or 8 long, fine 

 hairs especially long anteriorly ; pile absent posteriorly 

 and bristles absent. Sternopleuron, pteropleuron, and 

 hypopleuron apilose, the latter has an oval patch of 

 high pubescence. Mesopleuron with a vertical row of 

 5 to 7 long, slender bristles, lateral slopes of the meta- 

 notum micropubescent only. Lateral metasternum with 

 numerous, fine, long hairs throughout its length ; ventral 

 metasternum with somewhat fewer, shorter hairs; post- 

 metacoxal area membranous and pubescent; tegula 

 pubescent only. Prosternum not dissociated. 



Legs: The femora, tibiae, and tarsi are slender; the 

 hind femur is very slightly thickened beginning near 

 the basal third but not swollen. Dorsal pile of the 

 femora abundant, fine, rather short and subappressed. 

 Ventrally the hind femur has some short, more nearly 

 erect, similar, but scanty, bristly pile in addition to 

 scattered, long, fine, bristly hairs. The following com- 

 plement of bristles is present : a pair of stout, conspicu- 

 ous, subapical bristles, 1 dorsomedial, 1 dorsolateral, 2 

 prominent ventrolateral bristles, one of them at the 

 outer third, 4 prominent ventrolateral bristles, 1 at the 

 outer third and 3 situated before the middle, and a row 

 of 5 longer, slender bristlelike hairs ventromedially. 

 The trochanters have 1 stout and 1 slender ventral 

 bristle; hind tibia with stout, moderately long bristles, 

 2 dorsomedial at the basal and apical third, with at the 

 same point basally a ventromedial and dorsolateral, 

 and at the same point apically a still more stout lateral 

 bristle, and at the apical fifth a ventrolateral bristle. 

 Apex with 1 dorsomedial, 2 medial, 1 ventromedial, 1 

 dorsolateral, 1 lateral, 1 ventrolateral, and 2 long and 

 2 short ventral bristles. Middle femur with a pair of 

 stout, subapical, dorsomedial, and dorsolateral bristles 

 comparable to those of the hind femur. Ventral surface 

 with fine, long, bristly hairs. Middle tibia with strong 

 and moderately long bristles ; 3 anterodorsal, 3 postero- 

 dorsal, 2 or 3 posteroventral bristles on the distal half, 

 and 2 long, strong, ventral bristles at the basal and 

 apical third. Anterior femur with 1 stout, subapical, 

 posterodorsal bristle, its tibia with 3 fine, anterodorsal 

 bristly hairs, 2 or 3 posterodorsal bristles, 3 postero- 



