DASVPOGOXINAE 



ROBBER FLIES OF THE WORLD 



37 



Palpus clearly of two segments; both segments small, 

 short and robust, the first segment cylindrical and not 

 excavated and not fused; the second segment bears a 

 small apical pore. The first palpal segment bears 

 long, fine pile ventrally; the second has stiff, bristly 

 hairs ventrally, and laterally near the base, and sim- 

 ilar hairs dorsally and subapically. 



The antenna is attached at the upper fifth of the 

 head; it is elongate, slender, slightly longer than the 

 head. The first two segments are elongate and of 

 nearly equal length. The third segment is slender, not 

 quite, as wide as the end of the second segment, with 

 parallel sides to the middle and tapering gently to its 

 ventrally oblique apex; it is slightly longer than the 

 combined length of the first two and bears a stout, short, 

 robust microsegment ; its large, apical opening is dorsal, 

 oblique and has a short spine. Pile of first segment 

 restricted to the ventral and ventrolateral areas and 

 consists of 10 to 12 stiff, oblique setae; apex with 2 or 3 

 quite long setae. Second segment with 5 setae above, 

 the same number of longer, stouter setae below. 



Head, anterior aspect: Face below antenna about 

 one-ninth the head width. The face is slightly diver- 

 gent on the upper half; at the bottom of the eyes the 

 face is strongly divergent, its width one-third the head 

 width. Subepistoma short. The face is pubescent and 

 bears on each side submedially a single vertical row of 

 10 long, slender curled bristly hairs which begin at the 

 base of the antenna. Lower middle of the face above 

 the epistoma with a triangular area containing numer- 

 ous, long, stout bristles directed obliquely downward; 

 this group contains at least 25 elements. The front is 

 quite narrow, slightly wider than the face below an- 

 tenna; it has parallel sides continued to the vertex. 

 Sides of front with four slender bristles; the vertex is 

 scarcely excavated, the ocellarium moderate in height, 

 rising above the eye margin and bearing 5 or 6 paii-s of 

 slender, moderately long, anteriorly directed bristles. 

 Eye facets slightly enlarged. 



Thorax : Mesonotum of moderate height, with dense 

 velvetlike pubescence on each outer third, the medial 

 portion of the mesonotum nonpollinose. Pleuron 

 densely micropubescent, the mesopleuron chiefly bare. 

 Pile of mesonotum scanty and fine, consisting of long, 

 erect, subappressed setae. It bears a single row of acros- 

 tical bristles, an irregular double row of dorsolateral 

 bristles which vary in length from short to very long 

 and which, opposite the wing, become quite long, com- 

 prising 6 to 8 long bristles extending to the scutellum. 

 Humerus with weak bristles ; the margin from the hu- 

 merus to the suture with numerous stout bristles and 

 bristly hairs. The notopleuron bears 2 or 3 stout bristles 

 in front. Supraalar has from 2 to 4 stout and 4 weak 

 bristles. Postalar has 1 or 2 long and stout and several 

 weak bristles. Scutellar margin with a single pair of 

 stout bristles or 2 to 8 pairs of slender, weak bristles or 

 bristly hairs. Propleuron with abundant, long, fine 

 pile, the collar with 3 or 4 pairs of weak bristles and 

 stiff pile. Mesopleuron apilose or with 8 or 9 long 

 slender bristly hairs. Metapleuron with a vertical row 



of 7 or 8 long slender bristles and additional pile before 

 and behind. Metanotal callosity micropubescent only. 

 Metasternal slopes with numerous long hairs, the meta- 

 sternum densely long pilose, the postmetacoxal area 

 membranous. The metasternum is narrow but rolled 

 out and forward into a low transverse convex ridge. 



Legs : All the femora and tibiae slightly elongate and 

 comparatively slender, the hind pair especially so. The 

 hind femur is slightly and gradually thickened towards 

 the apex ; its tibia thickened near the apex. The hind 

 femur bears scattered, appressed setae dorsally, except 

 near the base, and these continue down the upper half 

 of the lateral surface ; stout, sharp bristles are present as 

 follows : 2 dorsomedial at the apex, 1 dorsolaterally at 

 the apex, a single stout, medial bristle at the apical 

 seventh, laterally a row of 4 stout bristles, row may con- 

 tain as many as 9 bristles ; ventrally on the basal half are 

 3 long, slender, attenuate bristles with a scanty row of 

 fine, erect pile. The hind tibia bears 3 to 5 stout, long, 

 dorsal bristles, 2 or 3 dorsolateral and 3 or 4 ventrolat- 

 eral ; apex with 12 bristles. The middle femur bears 1 

 to 3 dorsolateral apical bristles, 3 to 5 stout, anterior 

 and only a fringe of long, fine pile ventrally. Its tibia 

 has 5 weak dorsal, but of its 5 anterodorsal bristles, at 

 least 3 are long and strong ; it bears 4 to 6 long, strong 

 posterior, and 2 to 3 long, strong, oblique, ventral 

 bristles. Anterior femur with 2 weak dorsoapical 

 bristles and 1 to 3 stout, anterior apical bristles; its tibia 

 has a double dorsal row of short, stout bristles each con- 

 taining 3 to 6 bristles and posterior row with 4 or 5 

 long, stout bristles. Apex of anterior tibia without 

 trace of spine. Tarsus ends in slender, long, spatulate 

 pulvillus; claws long and sharp. 



Wings : The marginal cell widely open ; the anterior 

 branch of the third vein ends at or barely above the 

 wing apex; the posterior branch ends well behind the 

 apex; base of second submarginal cell arched forward. 

 First posterior cell fully open; both end veins of the 

 discal cell of approximately equal length; the fourth 

 posterior cell closed with a long stalk. Anal cell widely 

 open ; ambient vein complete. 



Abdomen: The abdomen is comparatively slender 

 and subcylindrical, slightly shorter than the wings. 

 Sides of the first tergite swollen laterally; 7 well de- 

 veloped tergites present in the male, the eighth appear- 

 ing as a narrow, short, flap in the middle and right side 

 only, or this segment completely concealed. Eight ter- 

 gites present in the female, the eighth nearly as long as 

 the seventh. Pile of abdomen short, appressed and 

 setate in the middle of the tergites and becoming long 

 and fine narrowly along the lateral margins. Sides of 

 first tergite with 5 or 6 long, slender bristles, absent on 

 the remainder of the abdomen. Sternites with long, 

 slender, erect, bristly hairs. Male terminalia in the 

 type of genus is fully rotate, the hypandrium forms a 

 curled process, short on some species, in others greatly 

 elongate and curled downward apically over the re- 

 mainder of the terminalia. The epandrium is fully 

 cleft, and developed into superior forceps, which are 

 robust, convex and conspicuous and each with a long, 



