LAFBR1INAE 



ROBBER FLIES OF THE WORLD 



337 



of 8 to 10 pale, dorsolateral, the distal ones rising until 

 they are almost dorsal in position and ending at the 

 outer fourth of the femora, the dorsal setae beyond this 

 point rather dense, stout and appressed and* oblique ; 

 ventrolateral surface and the ventral surface with only 

 a few, rather short, bristly hairs. Hind tibia with 

 quite short, bristly hairs only, bristles absent; ventral 

 surface with on the outer fourth a brush of setae that 

 medially occupies the distal half. Middle femur with 

 short, bristly pile anteriorly and posteriorly, its tibia 

 with a conspicuous anterodorsal row of 7 long, pale 

 bristles, the first 2 short, and with 5 short, postero- 

 dorsal, bristly hairs, 4 slender, posteroventral bristles, 

 and 1 rather stout ventrodistal bristle. The anterior 

 femur is like the middle pair ; its tibia has 6 or 7 short 

 but stout, sharp, anterodorsal bristles confined to the 

 basal half and with only ventral hairs and with 4 

 longer, posteroventral, slender, bristles or bristly hairs. 

 Apex without spine. All of the tarsi comparatively 

 short, especially the intermediate segments. Anterior 

 basitarsus as long as the next three segments; hind 

 tarns likewise. Claws sharp, strongly curved apically 

 with well developed but exceptionally wide, nearly 

 quadrate pulvilli ; the empodium is as long as the claw 

 and bladelike. 



Wings : The marginal cell closed with a rather long 

 stalk ; the anterior branch of the third vein is nearly or 

 quite straight and ends at the wing apex or barely 

 above it ; the posterior branch ends considerably to the 

 rear. First posterior cell open in maximal width, 

 fourth posterior cell closed, with moderately long stalk, 

 gently convex anteriorly and distally ; the anal cell is 

 closed with a long stalk, the middle end vein of the 

 second basal cell is a third as long as the upper vein; 

 the anterior crossvein enters the discal cell at the basal 

 fourth; the alula is wide, not distally produced; the 

 ambient vein complete. 



Abdomen : The abdomen is short and robust, as wide 

 as the thorax and three- fourths as long as the wing; 

 the sides are parallel to the end of the fourth segment, 

 considerably narrowed beyond. There are eight seg- 

 ments in the female, both the last two segments short ; 

 the seventh segment is almost completely concealed be- 

 neath the sixth being less than one-tenth as long as the 

 sixth ; the eighth is a little longer and more narrow and 

 less than one-third as long as the sixth. Ninth segment 

 short, divided completely in the middle and conical or 

 subtriangular, without any ventral process. The ven- 

 tral space is enclosed by 5 pairs of long, rather stout 

 bristles which extend far beyond the terminalia. Pile 

 of the abdomen abundant but quite short, flat appressed 

 and setate. Abdomen chiefly shining, often with 

 posterolateral triangles of pollen. These asilids prob- 

 ably mimic certain wasps. In the material before me 

 the last two tergites are red. First sternite apilose. 



Distribution: Neotropical: Pholidotus anceps Her- 

 mann (1912) ; rubriventris Hermann (1912) ; nificaudis 

 Hermann (1912). 



Genus Storthyngomerus Hermann 

 Figures 253, 617, 1218, 1227, 1572, 2114, 2141 



Storthyngomerus Hermann, Deutsche Ent. Zeitschr., 1919, p. 

 337, 1919. Type of genus: Dasypogon tridentatus Fabri- 

 cius, 1805, by original designation. 



Nusina Curran, Amer. Mus. Novitates, no. 272, p. 7, 1927. Type 

 of genus: Laphria dymes Walker, 1855, by original desig- 

 nation. 



Medium size flies of short, robust form and excep- 

 tionally short, minute, appressed pile. The dorsal ly 

 dilated hind femur has 4 or 5 tuberculate spines. The 

 face is deeply concave across the middle and the third 

 antennal segment is exceptionally and conspicuously 

 long. Length 12 to 17 mm. 



Head, lateral aspect: The head is comparatively 

 long, partly due to the strongly protuberant face and 

 the very greatly thickened ventral occiput. The upper 

 occiput is only shortly visible, the lower portion not 

 only more swollen but more prominent because of the 

 marked recession of the eye. The ventral occipital pile 

 is fine and abundant, becomes slender and bristly in 

 character; across the middle this bristly pile is dense 

 and extends deeply inward along the upper eye corners 

 where it is submarginal. There is a row of 8 to 10 

 stout bristles grading off below into the finer elements; 

 also another group of 5 or 6 bristles perhaps a little 

 more slender situated medially behind the vertex. The 

 upper face is protuberant, forming a sort of antennal 

 process, the middle of the face is nearly but not quite 

 plane with the eye and there is a prominent, rounded, 

 protuberant elevation on the lower half of the face 

 which retreats below, leaving the central face deeply 

 concave. Proboscis long, extended far beyond the face 

 with blunt, more or less transverse apex and the whole 

 structure greatly compressed laterally; it is punctate 

 at apex with fine, ventral hairs, the only other hairs lie 

 on the short, swollen base. Palpus small, cylindrical, 

 clearly of two segments ; the first segment is excavated, 

 the second with 6 or 7 stout, apical bristles and some 

 central, fine pile. The antemia is attached at the upper 

 third of the head and is set on an anterior protuberance 

 of front and face. The first segment is more than twice 

 as long as the second, the second is barely longer than 

 lush. The third segment is more than four times as 

 long as the combined length of the first two segments ; 

 it is slender, of nearly uniform width, with a minute 

 pit at apex. 



Head, anterior aspect: The head is nearly twice as 

 wide as high. The face below the antenna is less than a 

 fourth the head width, with nearly parallel sides and 

 only slightly widened at the level of the cheeks. The 

 upper face is thinly pollinose, the middle and gibbosity 

 bare. There is an oblique row of slender bristles on each 

 side of the upper half of the face extending to the anten- 

 nal base. The lateral margins have a narrow band of 

 silvery scales or flattened pile. On the gibbosity, widely 

 separated, is a vertical row of 7 long bristles, some of 

 them stout, besides between these rows above the epis- 



