DASVPOGONINAE 



ROBBER FLIES OF THE WORLD 



161 



and thickness. The proboscis is long, strongly com- 

 pressed laterally, attenuate, the lower surface nearly 

 plane, the dorsal arch or slope gentle and the apex 

 pointed, with rather abundant fine pile. It is directed 

 nearly straight downward. The ventral portion on the 

 basal half has numerous fine, long hairs. Palpus 

 clearly of two segments, first segment excavated with 

 stiff, long ventral pile, the second segment cylindrical 

 with a number of bristles and bristly hairs ventrolater- 

 ally but with an especially dense tuft of long, curled 

 bristles apically ; apex porate. The antenna is attached 

 at the upper third of the head; the first two segments 

 relatively short, the first a little longer than the second. 

 The third segment is about IV2 times as long as the first 

 two, thickened distally, strongly attenuate on the basal 

 half, swollen distally but with the apex greatly nar- 

 rowed, truncate, and bearing a short, visible, dorsal 

 spine. First and second segment ventrally with numer- 

 ous, long, stiff, pale bristles, with some shorter bristles 

 basally and laterally on the first segment and dorsally 

 on both these segments. 



Head, anterior aspect: Face below antenna one- 

 fourth of head width and divergent below. Sub- 

 epistomal region only moderately large, wide, concave, 

 bare. The face is pubescent with fine, long, stiff, bristly 

 pile laterally beginning shortly beneath the antenna 

 but with only a band of micropubescence along the eye 

 margin. Gibbous portion of face in the middle with 

 exceptionally long, stout, attenuate, pale bristles, more 

 or less bordered on either side by more dense, slender, 

 shorter, similarly colored bristles that extend down the 

 upper half of the subepistomal margins; the central 

 bristles of the face reach almost the apex of the pro- 

 boscis. Front pollinose, with a row of 6 stout, and 5 or 

 6 weak, long, subocular bristles and a submedial patch 

 of flat appressed bristles which may be long and di- 

 verge outward. Vertex but little excavated; the ocel- 

 larium is large but quite low, the ocelli large and bear- 

 ing across the middle 1 to 2 pairs of stout, long bristles 

 with additional bristly hairs and between the posterior 

 ocelli 1 pair of stout, long bristles. Anterior eye facets 

 enlarged. 



Thorax : The thorax is pollinose, pile of mesonotum 

 rather scattered, long, coarse, opaque, more or less ap- 

 pressed and bristly ; there is a double row of long, stout, 

 anterior, acrostical bristles consisting of some 6 or 7 

 pairs. The dorsocentral bristles are also quite long and 

 stout with 9 or 10 in each row. Humerus with 3 or 

 4 slender bristles and some pile. The following com- 

 plement of bristles is present laterally: 3 very long, 

 stout, posthumeral ; a row of 4 or 5 notopleural, which 

 may be reduced to 3 ; 4 to 6 supraalar ; 3 to 4 postalar ; 

 and 3 to 4 pairs on the scutellum. Scutellum thick, 

 convex, pollinose, with coarse, long pile laterally. In 

 addition to the bristles on the mesonotum, there may be 

 a rather dense, medial band of long, matted pile which 

 is manelike. Propleuron with exceptionally dense pile, 

 pale, opaque, matted, intermixed with the exaggerated 

 ventral pile of the occiput and the upper pile of the 

 coxa. Anterior collar with a wide band of bristly 



pile, long radiating and conspicuous with the more 

 anterior elements accentuated. Posterolateral prono- 

 tum with 12 or more long, slender bristles. The upper 

 half of the mesopleuron, anterior and posterior sterno- 

 pleuron and the posterior hypopleuron with abundant, 

 long pile. Upper pteropleuron with a tuft of long 

 hairs, the metapleuron with a vertical band of long, 

 slender bristles ; lateral slopes of the metanotum with a 

 patch of bristly pile. Postlateral metasternum and 

 ventral metasternum with abundant long pile, post- 

 metacoxal area membranous and pilose. Tegula with 

 setae; anterior basalare with 5 or G long, coarse hairs. 



Legs : All the femora are stout ; the anterior femur is 

 a little thickened towards the base, the dorsal, lateral 

 and anterior pile is abundant, sometimes very abun- 

 dant, coarse and more or less flat appressed. The fol- 

 lowing complement of bristles is described for the type 

 of genus: hind femur with 10 to 12 dorsolateral ; with 8 

 to 10 additional, equally long but more stout lateral 

 bristles; with 4 or 5 stout, subapical, dorsal bristles. 

 The ventral surface with abundant, long, fine, bristly 

 pile. Hind tibia with 12 or more dorsolateral bristles, 

 the row irregular and partly doubled, 2 or 3 stout 

 medial bristles on the basal half, more than 12 antero- 

 dorsal, 4 anterior, 5 anteroventral, and 3 or 4 ventro- 

 medial bristles. Middle femur with a very long, 

 posterior brush of fine pile and with 2 bristles postero- 

 dorsally subapically, and 6 anterior bristles. Middle 

 tibia with very stout, distally attenuate, quite long 

 bristles: 8 anterodorsal, 4 dorsal beginning at the basal 

 third, 5 or 6 posterodorsal, 5 posterior, the middle 3 ac- 

 centuated, and 3 or 4 posteroventral bristles. Anterior 

 femur with a posterodorsal, spikelike cluster of ex- 

 ceptionally long bristles from near the base to near 

 the apex, which contains aboutl5 elements or sometimes 

 fewer. Posteroventral margin with the same dense, 

 long, matted fringe of coarse opaque pile found on 

 the middle femur; these fringes are present in males 

 only. This tibia has short, stout bristles for the most 

 part: 7 or 8 anterodorsal, a like number of posterodor- 

 sal, 5 or 6 long, stout posterior and at least 3 or 4 long, 

 stout, ventral bristles, besides additional, long, bristly 

 pile posteriorly and ventrally. Apex of all the tibiae 

 and the slender tarsi with long, sharp, stout, greatly 

 accentuated bristles. Anterior basitarsus with a circlet 

 of 10 bristles; all tarsi end in sharp, slender claws and 

 with short, small pulvilli and long bladelike empodia. 



Wings: The whole wing is vitreous hyaline. Mar- 

 ginal cell open by less than its maximum width; sub- 

 costal cell rather narrow ; anterior branch of third vein 

 ends above the wing apex; posterior branch ends be- 

 hind by an equal distance. First posterior cell closed 

 with a long stalk ; base of second posterior cell strongly 

 and abruptly swollen anteriorly; upper end vein of the 

 discal cell very short, the lower vein greatly drawn back 

 towards the base, the angle formed by this vein and the 

 end vein of the fourth posterior cell is 135 degrees. 

 Fourth posterior cell closed with a long stalk; anal 

 cell closed with a very short stalk; alula of moderate 

 width ; ambient vein complete. 



