ROBBER FLIES OF THE WORLD 



503 



long, slender, ventral elements near the base. Hind 

 tibia, which is long and slender and nearly as long 

 as the femur has 3 dorsal, 1 dorsomedial beyond the 

 middle, 1 stout ventrolateral bristle on the apical fourth, 

 and 2 or 3 additional, fine, long hairs ventrolaterally. 

 There is no brush of setae ventrally. Hind basitarsus 

 long and slender, slightly longer than all the remaining 

 segments of the tarsus. Middle femur with 3 rather 

 stout, sharp bristles anteriorly, 2 on the basal half, 1 

 just beyond the middle, 1 posteroapical, and 3 unusu- 

 ally prominent, long, stout bristles posteroventrally on 

 the basal half; also with 7 almost equally prominent, 

 ventral bristles, most of them on the basal half. This 

 tibia has a fine, slender bristle dorsally in the middle 

 and 2 fine, short, hairs dorsally before the middle. There 

 is a single, quite long, stout, posteroventral bristle at 

 the outer third matched by a similar, anteroventral 

 bristle and with an additional anteroventral bristle at 

 the middle. On the basal half there are 4 extremely 

 fine, long, posteroventral hairs. 



Anterior femur with 4 long, stout, ventral, basal 

 bristles ; its tibia has 2 exceptionally long, posteroven- 

 tral bristles near the middle, and 2 weak, rather short 

 dorsal bristles. The brush of setae begins at the basal 

 third : the ventral bristles at the apex are exceptionally 

 long, the tarsal bristles moderately long, the basitarsus 

 as long as the next 3 segments. All tarsi end in slender, 

 sharp claws, strongly curved on the outer half, large 

 pulvilli and empodium thickened near the base. 



"Wings : The marginal cell closed with a stalk of me- 

 dium length ; the anterior branch of the third vein ends 

 at the wing apex ; the posterior branch ends at a con- 

 siderable distance behind the apex, equal approximately 

 to the difference between the ends of the second and 

 tMrd veins. The second submarginal cell is towards the 

 base, gradually and progressively widened; first and 

 second posterior cells widely open. Fourth posterior 

 cell closed with a long stalk, straight posteriorly and 

 rather strongly convex anteriorly and distally; the 

 lower end vein of the distal cell is pulled strongly back 

 toward the base of the wing. Anal cell closed; alula 

 moderately wide, the ambient vein complete. Wing 

 avillose, except in the subcostal and the end of the sub- 

 marginal cells. 



Abdomen : The abdomen is slender, subcylindrical 

 but with a very slight flattening across the middle of the 

 tergites; the sides are nearly parallel to the end of the 

 fifth tergite and the sides are rolled. Pile of the ab- 

 domen very scanty, fine, short and appressed ; the sides 

 of the first slightly protuberant tergite bear fine, long, 

 stiff hairs ; lateral postmargin of the remaining tergites 

 with 4 or 5 long, stiff hairs. First stemite without pile ; 

 remainder with a few, fine, long hairs. Eight tergites 

 present in the female ; the eighth is two-fifths as long as 

 the seventh, the seventh nearly as long as the sixth. 

 Female terminalia extremely short, the ninth tergite is 

 broad dorsally and slightly depressed; considerably 

 wider at the base than long ; the tenth is a little longer 

 than wide at the base and turned downward. Both 

 ninth and tenth segments are turned downward. 



Distribution: Neotropical : Opopotes atteniuitus Hull 

 (1957). 



I have before me a second species wMch is mide- 

 scribed, and also Neotropical. 



Lycoprosopa, new genus 

 FiQUBES 382, 788, 1547, 1556, 2196, 2269, 2488, 2489 



Type of genus : Asihis atrimaculatus Hobby, 1934. 



Medium size flies, characterized by the extraordi- 

 narily long, slender, second submarginal cell, the fork 

 of the third vein situated before the end of the discal 

 cell, by the narrow face, together with the narrow, long, 

 third antennal segment and somewhat dilated aristal 

 apex. It is distinguished from Lecania Macquart by 

 the presence on the scutellum of a distinct, hnpressed 

 rim, a male superior forcep which is greatly narrowed 

 at the base and a female ovipositor which like Astochia 

 Becker is composed of six segments. Length 18 to 27 

 mm. 



Head, lateral aspect: The head is comparatively 

 short, the face plane with the eye except on tlie lower 

 third which is only slightly produced and chiefly evi- 

 dent on accomit of the recession of the eye. The face 

 is almost entirely plane. Occiput poorly developed 

 both below and above and a little more extensive along 

 the middle ; ventrally it bears scattered, fine hairs. The 

 base behind the proboscis bears on each side a separated 

 tuft of longer, radiating hairs. The upper occiput has 

 weak bristles in the middle and slender bristles at the 

 upper eye comers. The proboscis is slender and rather 

 pointed at the apex which bears fine hairs. The ventral 

 surface at the middle has 5 or 6 long, oblique hairs ; the 

 base has a tuft of 10 or 12 hairs. Palpus quite slender 

 and long, with 2 long, apical bristles and shorter, fine 

 hairs along nearly the whole surface. The antenna is 

 attached near the upper third of the head ; the first seg- 

 ment is slender and about four times as long as wide 

 and more than twice as long as the second segment. 

 Both bear rather numerous, long setae ventrally and 

 near the apex short setae dorsally. Third segment 

 slender, more narrow than the second; it is attenuate 

 on its distal half and has 1 dorsal seta and the style is a 

 little thickened at the apex and tipped with a bristle. 

 The style is 1^/2 times as lono; as the third segment. 



Head, anterior aspect : The width of the head is about 

 11/^ times the height of the head. The face below the 

 antenna is quite narrow, and about a tenth the head 

 width. It is strongly divergent below where it is more 

 than twice the upper width. Surface densely ap- 

 pressed, micropubescent with a vertical row of 5 stiff 

 hairs on each side, and clustered closely in the middle 

 above the epistoma is a group of about 20 long, stout, 

 whitish bristles reaching to the end of the proboscis; 

 there are 1 or 2 others along the sides of the sub- 

 epistoma, which is narrow, deeply concave, pollinose. 

 Cheeks very short. The front is only very slightly 

 wider than the upper face, but the vertex is distinctly 



