DASTP0G0N1N4B 



ROBBER FLIES OF THE WORLD 



185 



is thick with dense, long pile, the outer elements a little 

 stiffer and more bristly in appearance. Proboscis short, 

 robust, directed nearly straight forward, and laterally 

 compressed; it is gradually swollen towards the base 

 from the dorsal aspect but with minute pile and bluntly 

 rounded. Palpus clearly of two segments, the first seg- 

 ment short, excavated, the second elongate but slender 

 and cylindrical with a few fine, ventral and lateral 

 hairs. The antenna is attached at the upper third of 

 the head; it is elongate and quite slender. The first 

 segment is l 1 /^ times as long as the second. The third 

 segment with the microsegment included is twice as 

 long as the first two combined ; it is much less wide than 

 the second segment but is a little wider near the base. 

 This segment is cylindrical and bears two microseg- 

 ments; the first is short, obliquely and ventroapically 

 truncate; second is longer, at its tip a spine directed 

 obliquely downward, its length one-fourth the length 

 of the third segment. First two segments with numer- 

 ous, long, dorsal, ventral, and lateral bristles or bristly 

 hairs all quite slender. 



Head, anterior aspect: The face below the antenna 

 is less than one-fourth of the head width and strongly 

 divergent below. The front and vertex are nearly the 

 same width as the upper face. Subepistomal area 

 large, oblique but well concealed by the dense pile and 

 proboscis. Face densely micropubescent with a wide, 

 dense, medial band of exceedingly long, slender, bris- 

 tles that extend well beyond the antenna and far be- 

 yond the proboscis. Front pubescent on the side, with 

 a wide band of many long, bristly hairs. Vertex mod- 

 erately excavated, the ocellarium large, all the ocelli 

 quite large, and in the middle with a tuft of 15 to 20 

 long, slender bristles and several additional pairs 

 behind the ocelli. Anterior eye facets enlarged. 



Thorax : The thorax is thinly, minutely micropubes- 

 cent. Pile of mesonotum abundant, long, fine and 

 bristly in character. There is a dense, narrow band 

 of long, slender bristles down the middle of the meso- 

 notum for its full length. Dorsocentral elements are 

 poorly or not at all differentiated anteriorly but be- 

 come an irregular band posteriorly, long and slender 

 but less dense than the medial band. Humerus with 

 numerous, long, stiff, bristly hairs. Lateral margins 

 with numerous long, slender bristles: notopleuron with 

 6 to 8, supraalar area with 10 to 12 in 3 rows, postalar 

 with 8 to 10 and the posterior margin of the scutellum 

 with a wide band of which the lower row contains 6 

 or 8 pairs of bristles, the remainder of the scutellar 

 disc with some shorter, fine pile. Propleuron with 

 abundant, long, fine pile including the collar. Bris- 

 tles absent. Upper and posterior half of mesopleuron 

 with numerous, long, stiff hairs. Anterior and poste- 

 rior sternopleuron with some fine hairs. Pteropleuron 

 and hypopleuron apilose. Almost the whole of the 

 convex metapleuron densely covered with long, slender, 

 orange bristles and bristly hairs. Metanotal slopes 

 micropubescent only; lateral met a sternum with long 

 pile posteriorly, similar dense pile on the ventral meta- 



sternum, the postcoxal area membranous; tegula with 

 setae. 



Legs : All the femora are slender ; hind femur and its 

 tibia especially slender and a little more elongate. The 

 dorsal pile of the hind femur short and subappressed 

 medially, becoming longer and somewhat bristly in 

 character laterally; ventrally there is a rather dense 

 fringe of short, nearly erect, stiff pile on the medial 

 aspect intermixed with fine, long hairs on the basal half 

 and 6 or 7 others situated distally and ventrally. There 

 is a dense, posteroventral fringe of pile on the middle 

 femur on the basal half; its dorsal pile is extremely 

 long and fine and these flies bear the following comple- 

 ment of bristles or bristly hairs: On the hind femur 

 laterally 18 to 20, which are long and tend to be dor- 

 solateral, with fewer shorter, more lateral elements ; on 

 this tibia a conspicuous, medial row of 10 or 11 long, 

 slender elements and similarly conspicuous dorsal row 

 of 12 to 14, with 8 or more anterodorsal and 8 ventral 

 bristles. Middle femur with dense, slender bristles an- 

 teroventrally on the basal half intermixed with equally 

 long, fine pile; middle tibia has 10 anterodorsal bristles, 

 besides in front of them an additional row of somewhat 

 shorter, fine hairs. Also it has several rows of extremely 

 fine hairs dorsally and posterodorsally, besides 10 sim- 

 ilar, still longer hairs posteriorly and 10 to 12 elements 

 ventrally. 



Anterior femur at base in males with a long, stout, 

 hammerlike process. The bristles of the anterior femur 

 are similar to the middle leg but the tibial bristles are 

 shorter and somewhat more numerous posteriorly. 

 Apex without spine. Anterior basitarsus in the male 

 arched, bent backward at the apex so that it is strongly 

 concave from its lateral aspect; next 3 tarsal segments 

 very short and progressively smaller. Tarsi end in 

 sharp, small claws, large pulvilli and slender, bristlelike 

 empodium. 



Wings: The wings are widest in the middle, the 

 costal cell wide, the subcostal cell characteristically and 

 greatly narrowed. The marginal cell open. Second 

 submarginal cell with nearly parallel sides; all the 

 posterior cells and the anal cell widely open. The 

 anterior crossvein enters the discal cell at the basal 

 fourth ; the second basal cell ends with 3 veins and the 

 alula appears to be absent or confined to a veiy nar- 

 row, slender strip. Ambient vein complete. Males 

 may have a black spot and females with a dusky spot 

 at apex. 



Abdomen : The abdomen is somewhat compressed lat- 

 erally; first tergite raised in the middle posteriorly 

 and eight tergites in the male, the eighth tergite only 

 one-fourth as long as the seventh. Females with 

 eight tergites, the eighth also only one-fourth as long 

 as the seventh. Pile of the abdomen is long and dense, 

 strongly flattened along the sides of the last three ter- 

 gites in the male only. Bristles are absent, including 

 the first tergite; the pile is longer on the sides of the 

 first three tergites. Male terminalia are short, not 

 rotate or at most only slightly turned to the left. Hy- 

 pandrium undivided; superior forceps very short. 



