ROBBER FLIES OF THE WORLD 



597 



OLIGOCENE: 



EOCENE: 



3 genera (2, extinct) ■ 3 species 



Text-Figure 35. — A provisional philogenetic arrangement of the Asilidae. 



than the face and situated from the base of the antennae to the 

 oral border ; front as wide as the face ; ocellar callosity with a 

 pair of bristles ; proboscis cylindrical, small ; palpus small, as 

 long as one fourth the length of the antennae and with minute 

 pile. Antennae with the first segments cylindrical, slightly 

 larger than the second, third segment oval and as large as the 

 first segment; arista a little longer than the basal segment of 

 the antennae with a small shining segment or joint (articulocao) 

 at the top of the proximal fifth. 



Thorax : Mesonotum normally convex. Lateral bristles and 

 dorsocentral bristles well developed ; the bristles of the scutellar 

 margin are fine ; lateral callosity of postscutellar region with 

 fine pile. 



Legs : Slender with fine bristles not abundant nor very long. 

 Claws sharp apically; pulvilli almost of the same size as the 

 claws. 



Wings : Rather shorter in extent than abdomen, and narrow ; 

 alula reduced. 



Abdomen : Delicate (fino) and long cylindrical. The first and 

 the second segments with very fine, elongate pile. In the re- 

 maining segments the pile is short; beginning with the third 

 segment the posterior margins of the tergites are equipped with 

 small bristles. Genitalia of the male set in the same direction as 

 the abdomen without any angle formed, as large as the seventh 

 segment; superior forceps with the triangular shape or form 

 (contorno). Genitalia of the female laterally compressed, 

 shining from the seventh segment ; this segment and ovipositor 

 together are as compressed as the extent of the combined fifth 

 and sixth segments. 



Distribution: Neotropical: Stenasilus tenuis Wiede- 

 mann (1828). 



