DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



283 



set in a single row quite deeply behind the eye, with 

 bristly pile in front. Proboscis prominent, rather 

 slender, except for the high, dorsal ridge or keel, which 

 is reduced near the apex. Apex rather pointed, with 

 fine pile which is continued below on the whole outer 

 half; the basal half bears numerous, fine, long hairs. 

 Upper surface of proboscis arched and convex. Pal- 

 pus large, conspicuous, the first segment excavated, the 

 second longer, robust, and bearing numerous bristles 

 and a large, apical pore. The antenna is long and 

 rather slender, longer than the head; the first two seg- 

 ments are rather short, subequal, each a little longer 

 than wide, each with short, appressed setae above and 

 several stout but quite short bristles ventrally. Third 

 segment barely wider than the second and slightly nar- 

 rowed on the outer fourth. The apex has an open pit 

 bearing a concealed spine. 



Head, anterior aspect: The head is wide with the 

 width almost twice the height and the eyes strongly 

 flattened in front. The face is wide, at least a fourth 

 the head width and slightly widened below. Surface 

 of face without pile and densely covered with excep- 

 tionally fine, appressed, silvery pubescence. There is 

 a partially doubled, transverse row of 14 stout, both 

 white and black, moderately long bristles above the 

 epistoma; no hairs or bristles present along the sides 

 of the epistoma. The front is slightly wider than the 

 upper face with on each half 2 distinct groups of mod- 

 erately long, slender bristles, 1 group submarginal and 

 separated from the more medial group by a shallow 

 fossa. Vertex only moderately excavated, with slanting 

 sides; the ocellarium is large, also with sloping sides, 

 and containing 2 pairs of rather long, stout bristles 

 between the posterior ocelli, and behind these 2 or 3 

 pairs of setae. The vertex is slightly narrowed. 



Thorax : The thorax is comparatively long ; the meso- 

 notum is slightly convex, more so behind and abrupt 

 anteriorly. It presents a very bare appearance due 

 to the scanty, minute, suberect setae and almost com- 

 plete absence of pile. The whole surface as well as 

 the pleuron is thinly pollinose, with pubescence devel- 

 oped only on the central part of the pleuron. There 

 is a single acrostical row of many stout, short setae 

 extending almost to the pronotum. Also dorsocentral 

 setae are numerous, with 1 or 2 short, stout bristles on 

 the posterior part of the mesonotum. Humerus with 3 

 short, stout bristles anteriorly and setae. Lateral bris- 

 tles exceptionally stout and long. There are 2 noto- 

 pleural bristles, 2 supraalar, 2 on the postalar callosity, 

 and 1 crossed pair on the scutellum. The scutellum 

 is large with a flat, pollinose disc, and a few minute 

 hairs. Pronotum with 6 pairs of moderately stout, 

 long, attenuate bristles; the ventrolateral portion im- 

 mediately above the front coxa has a very stout bris- 

 tle. Lateral metanotum with a long, oblique bulla and 

 pollen. Metapleuron with a vertical row of 4 stout 

 and long and 2 weak bristles. Pleuron otherwise with- 

 out pile, except for a curious, small patch of dense, erect 

 setae on the anteriormost portion of the mesopleuron 

 and some setae and hairs on the upper lateral part of 



the propleuron. Lateral and ventral metasternum with 

 pile; postmetacoxal area membranous; prosternum 

 dissociated ; anterior coxa with 6 ventral and 3 dorsal 

 bristles; middle coxa with 8 ventral bristles; posterior 

 coxa with 1 lateral bristle. 



Legs: All the femora and tibiae are exceptionally 

 stout; the first 4 femora are perhaps a little swollen 

 throughout most of their length; they are covered 

 throughout with scanty, appressed, short, stout setae 

 which are a little more numerous dorsally but evenly 

 distributed on the tibiae and tarsi. All bristles are 

 quite stout, the hind femur bears 1 lateral bristle at 

 the basal third, 1 much smaller bristle proximal to it, 

 no others. Hind tibia with 1 small dorsolateral bristle 

 at the base, 2 stout lateral bristles at basal and apical 

 third, 3 similar dorsomedial bristles, 2 to 3 equally 

 stout, prominent, ventral bristles on the outer half, 

 and a small ventromedial bristle at the base. Hind 

 basitarsus as long as the next three segments. Middle 

 femur with a single, exceptionally stout bristle poste- 

 riorly near the apex, another shorter bristle anteriorly 

 near the base. Anterior tibia with 2 small, basal and 

 1 very stout, conspicuous, anterior bristle located near 

 the middle with 2 small, dorsal bristles on the basal 

 half, a small, anteroventral bristle near the base and 

 6 medium size, stout, posteroventral bristles, besides 2 

 exceptionally striking, very stout, long, ventral bris- 

 tles located at the middle and beyond. Anterior femur 

 with a small bristle posteriorly near the apex, 2 weak, 

 short bristles ventrally near the base. Anterior tibia 

 with 6 short, stout, anterodorsal bristles, 3 similar, 

 posterodorsal elements, 5 short, posteroventral bristles, 

 and a single, conspicuous, long, distal and ventral bris- 

 tle. The terminal bristles are rather far removed from 

 the apex and the apex bears a large, short, distinct 

 protuberance, with a basally stout spine. Basitarsus 

 without swelling but with numerous, blunt denticles. 

 Claws stout, long, sharp ; the pulvillus quite long and 

 slender ; the long, very stout empodium bladelike. 



Wings : The wings are tinged with brown ; the mar- 

 ginal cell is open by considerably less than its maximal 

 width. The fourth posterior cell is closed and stalked 

 or very narrowly open. The anal cell is closed in the 

 margin; the alula is large; ambient vein complete. 

 The upper anterior intercalary vein is long and the 

 posterior crossvein almost eliminated. 



Abdomen : The abdomen is broad, robust, as wide as 

 the mesonotum and with parallel sides to the end of 

 the fourth segment. It is covered with numerous, 

 quite small, stout, appressed setae. Pile is absent, ex- 

 cept anterolateral^ on the first segment. Postero- 

 lateral margin of first segment with 5 or 6 spikelike 

 or spinous bristles. Males with seven tergites; the 

 seventh is two-thirds as long as the sixth. Females 

 with eight tergites and the eighth half as long as the 

 seventh. Male terminalia quite short, the epandrium 

 is cleft to the base and rather divergent and widely 

 separated. Each half is small and short. The proc- 

 tiger is very broad and short. The largest element is 

 the convex gonopod which extends a little beyond the 



