DASTPOGONINAB 



ROBBER FLIES OF THE WORLD 



231 



pressed. Sternites with short, fine pile, the first ex- 

 cepted. Only the first tergite with bristles ; 4 or 5 pairs 

 of stout, long bristles present. Male terminalia short, 

 rotate one-fourth to three-eighths. Terminalia of the 

 general form of Diogmites Loew and Allopogon 

 Schiner. The epandrium is short, fully cleft and di- 

 vergent from the base into two triangular halves with 

 the proctiger extending a little beyond. The gonopod 

 is the dominant element and large and swollen later- 

 ally with a pronged, distal extension from its true 

 dorsal apical corner. Hypandrium large, broad and 

 obtuse. Bristly hairs are moderately abundant but 

 slender and arise chiefly from the basal part of the 

 terminalia; the cavity is rather widely open and the 

 aedeagus forms a simple tube. Females with acan- 

 thophorites and 5 pairs of long, rather blunt spines; 

 ventral plate with a large apical medial, bowl-shaped 

 depression, the concave side down, the margins distally 

 with bristly hairs. 



Distribution : Neotropical : Caenarolia argyrocinctus 

 Schiner (1867) ; oasalis Curran (1935) ; longipennis 

 Thomson (1869) ; miles Wiedemann (1828) ; spitzi 

 Carrera (1949). 



Genus Diogmites Loew 



Fiqxjbes 94, 466, 549, 1056, 1065, 1797, 1798, 1997 



Diogmites Loew, Berliner Ent. Zeitscher., vol. 10, p. 21, 1866. 

 Type of genus: Diogmites platypterus Loew, 1866. Desig- 

 nated by Coquillett, 1910, the first of eight species. 



Large flies of drooping aspect and greatly reduced 

 pile, which is minute and setate. Most species are pale 

 in color with faint or indistinct bands or vittae of pollen. 

 The face is characteristically apilose, the bristles, which 

 are stout, are confined to a narrow band above the epis- 

 toma. Fourth posterior cell closed, the tliird antennal 

 segment with dorsal bristles and the ocellarium with 

 only 1 pair of stout bristles. Length 12 to 35 mm. 



Head, lateral aspect : The head is comparatively short 

 and wide, the face is well developed but never promi- 

 nent, produced or gibbous. It is extended forward 

 slightly more below than above and is nearly plane. 

 The occiput is poorly developed, not extending beyond 

 the eye except in the lower corner. The pile below is 

 unusually scanty and bristly in character. Bristles be- 

 gin near the bottom of the eye and near the middle of 

 the occiput form a single row of rather deeply sub- 

 lateral, stout elements. In addition on each side there 

 is a postvertical cluster of even stronger elements. Pro- 

 boscis is elongate, cylindrical, attenuate from near the 

 middle of the apex. The medial ridge is prominent 

 over the middle third, the apex pointed and the dorsal 

 surface gently arched. The ventral surface is slightly 

 concave. Palpus of two segments, more or less fused. 

 The basal segment is distinctly excavated, the second 

 sometimes with angulate attachment, clavate and porate 

 with numerous stiff bristles. The antenna is attached 

 a little above the upper third and is generally a little 

 longer than the total head length. The first segment 



Text-Figure 15. — Pattern of distribution of the genus Diogmites Loew 



of the antenna is shortest, the second with 2 stout, 

 ventroapical bristles. The third segment is dilated 

 through the middle, attenuate towards base, with a 

 number of short stout dorsal bristles and bearing a small, 

 completely fused microsegment. Apex of third seg- 

 ment with large, oblique, open pit and spine. 



Head, anterior aspect: The head is unusually wide, 

 the eye strongly flattened on each side with greatly 

 enlarged facets; the face below antenna varies from 

 about a fifth to a fourth the head width and may be 

 very slightly wider below. The face is densely pol- 

 linose and usually without pile; a few fine setae may 

 be present and above the epistoma is a conspicuous, 

 narrow, single or double row of rather long, stout 

 bristles which are generally pale in color. The sub- 

 epistoma is large, oblique, concave. Front is short, 

 flat, pollinose, of about the same width as the face, 

 with a few, fine, short, bristly hairs laterally. Vertex 

 scarcely excavated; the ocellarium is large but low 

 with a single pair of long, stout bristles and sometimes 

 one or two fine setae. 



Thorax: The mesonotiun is pollmose; the pile is 

 restricted to a few scattered, short setae. Acrostical 

 bristles or setae are differentiated; dorsocentral bristles 

 differentiated only along the middle and behind, and 

 of these there may be 2 or 3 long elements posteriorly. 



