ROBBER FLIES OF THE WORLD 



583 



pus quite slender and cylindrical ; it is rather long and 

 bears very fine pile, except at the apex, where there 

 is a tuft of 7 long, rather stiff, black bristles, 3 of them 

 lateral. The antenna is attached at the upper third 

 of the head and quite slender ; the first segment is twice 

 as long as the second ; the third segment is slender and 

 not quite as long as the first. It is rather strongly at- 

 tenuate distally and bears an unusually long, slender 

 style which is fully three times as long as the third 

 segment. There is a very short microsegment, ap- 

 parently. 



Head, anterior aspect : The face below the antenna is 

 a seventh the head width and twice as wide at the 

 epistoma. The subespistomal area is rather large but 

 narrow, V-shaped, deeply concave and pubescent. The 

 face is pubescent, almost without pile but with rather 

 nmnerous, quite stout bristles on the middle third of 

 the face ; this group widens toward the epistoma ; 7 or 

 8 of the dorsal bristles are black, and a little shoi'ter, 

 the middle and ventral bristles are pale and stouter and 

 reach slightly beyond the end of the proboscis ; similar, 

 long, pale bristles extend down the sides of the sub- 

 epistoma. Front comparatively short, bare medially, 

 pollinose laterally, with a row of 6 short, but stout 

 black bristles along the eye margin, an additional row 

 of 4 medial to these anteriorly, and 5 other bristles 

 obliquely in front of each antenna. Vertex only mod- 

 erately excavated, narrow, the sides vertical ; ocellarium 

 moderately large, rather low with a pair of short, black 

 bristles between the ocelli, a pair between the posterior 

 ocelli and 2 pairs of slightly longer bristles behind the 

 ocelli. Anterior eye facets strongly enlarged. 



Thorax : The thorax is pollinose. Pile of mesonotmn 

 abundant but short and quite bristly and stiff in char- 

 acter. Acrostical and dorsocentral elements are not 

 differentiated. Immediately in front of the scutellum 

 is a transverse band of somewhat longer, slender bris- 

 tles or bristly pile. Himierus with abundant, bristly 

 pile. Lateral bristles are exceptionally stout and rather 

 long and consist of 2 notopleural preceded by a weak 

 posthumeral, 2 supraalar followed by a strong supra- 

 postalar, 2 postalar, and 1 pair of scutellar bristles. 

 Scutellum thick, convex, with impressed rim, micro- 

 pubescent or pollinose, with nmnerous, erect, bristly 

 hairs on the disc, the basal crease deep. Propleuron 

 with rather scanty, short, fine pile; the pronotum is 

 thick, convex, prominent and bears 6 pairs of excep- 

 tionally stout, long, black bristles. The dorsal postero- 

 lateral pronotum bears abundant, fine, long pile only ; 

 mesopleuron with a dorsal band of bristly hairs; an- 

 terior and upper posterior sternopleuron with some long 

 pile ; pteropleuron with 2 or 3 slender, pale bristles and 

 additional pile; posthypopleuron with at least 3 long, 

 slender bristles and several bristly hairs; metapleuron 

 with a single, vertical row of 6 long, slender, pale bris- 

 tles and dorsally considerable additional, long, bristly 

 haii-s. Lateral slopes of the metanotum with a large 

 tuft of dense, long, bristly pile. The lateral meta- 

 stemum has abundant, long, bristly pile and the ven- 

 tral metasternimi likewise. Postmetacoxal area mem- 



branous; tegula with setae, posterior basalare with 7 

 or 8 rather long, slender, reddish bristles; anterior 

 basalare with 12 to 11 short to long, black bristles. 

 Male postpronotum with 7 or 8 slender bristly hairs 

 among the fine pile. 



Legs: The femora are comparatively slender, espe- 

 cially the hind pair. The huid tibia also slender and 

 as long as the femur; all the basitarsi comparatively 

 long. Dorsal pile of all the femora and the lateral pile 

 of the hind fem\ir abmidant, but very fine, setate and 

 subappressed. Ventral surface of all of the femora 

 with almost no pile, though the anterior four have a 

 very few, slender, bristly hairs or weak bristles on 

 their basal half. Medial surface of the hind femur 

 with a rather abundant row of comparatively long, 

 pale bristly hairs, the following complement of bristles 

 present : On the hind femur are 3 lateral bristles along 

 the middle, 1 stout, long, subapical, dorsolateral and 



1 submedial counterpart, 1 stout, centrolateral at the 

 outer third, 1 basal ventromedial, another medial at 

 the basal third ; hind tibia with a single, well developed 

 dorsomedial bristle just before the middle and 2 or 3 

 very fine, bristly hairs in the same row, and 3 or 4 

 stout dorsolateral and 1 ventrolateral at the outer 

 fourth; the ventral surface thickly beset with short, 

 oblique setae. Apex of the hind tibia with 1 dorso- 

 lateral, 1 ventrolateral, 1 ventral, and 1 ventromedial 

 bristle. The middle femur has 3 exceptionally stout, 

 long, anterior bristles along the middle, and basally 

 before these is an oblique row of 5 bristly hairs; anter- 

 odorsally are 3 exceptionally stout bristles as counter- 

 parts of the more anterior ones. Ventrally at the base, 

 are 3 long, slender bristles or bristly hairs. The middle 

 tibia has only short, fine bristly hairs dorsally, but has 

 3 posteroventral and 2 anteroventral bristles, somewhat 

 stouter on the outer half, and 1 ventral element beyond 

 the middle. 



Anterior femur very slightly thickened toward the 

 base with a short, weak, dorsal, subapical bristle; the 

 base ventrally has 3 slender, bristly hairs ; anterior tibia 

 with a short, weak anterodorsal bristle, which may be 

 absent, at the base, a similar dorsal at the middle, with 



2 longer, slender, posteroventral bristles beyond the 

 middle and 1 stout, anteroventral bristle at the outer 

 fourth ; apex with a pair of subdorsal and 6 rather stout 

 ventral bristles. All tarsi end in sharp, slender claws, 

 strongly bent at the apex ; long, slender pulvilli ; empo- 

 dium a little thickened on the basal half and two-thirds 

 as long as the claw. 



Wings : The wings are comparatively slender. Mar- 

 ginal cell closed with a moderately long stalk, subcostal 

 cell not expanded, the second submarginal cell takes 

 origin near the end of the discal cell, is somewhat di- 

 lated near its basal third, constricted on the outer third 

 due to the strongly flared first posterior cell; the first 

 posterior cell distally is tliree times as wide as its mid- 

 dle width. Second posterior cell strongly arched anter- 

 obasally, more than twice as wide as the end of the 

 discal cell; lower end vein of the discal cell very 

 strongly drawn backward and more than tliree times as 



