DASYPOGONINAE 



ROBBER FLIES OF THE WORLD 



269 



Text-Figure 17. — Pattern of distribution of the genus Cophura Osten- 



Sacken. 



and bare; the opposite facial fissures are rather deep. 

 The face is densely micropubescent ; also in type of 

 genus it bears on either side near the eye margins some 

 12 subappressed, fine, rather short hairs. This hair 

 tends to occupy the lateral third of the face. The front 

 is pubescent, very slightly widened, and bears 4 or 5 

 fine hairs laterally. Vertex but little excavated, the 

 ocellar protuberance however is conspicuous, with ver- 

 tical sides and bearing a very large anterior ocellus and 

 dorsally from 1 to 3 pairs of stout, divergent bristles 

 and rarely a few additional fine hairs. Anterior cen- 

 tral eye facets strongly enlarged. 



Thorax : The entire thorax is appressed micropubes- 

 cent, taking on more or less the character of the pollen 

 on the mesonotum. The mesonotum tends to be rather 

 high and arched, especially in front. The mesonotal 

 pile is fine and scanty in the type of genus, with a dis- 

 tinct row of acrostical elements present, followed by a 

 bare stripe and laterally undifferentiated, scattered, 

 dorsocentral elements which become quite long and 

 rather stout before the scutellum and are often strongly 

 curved backward to reach almost or to the scutellar 

 margin. Such differentiated elements in some species 

 may extend well forward in front of the transverse 

 suture nearly to the humerus. The type of genus 



possesses the following complement of long, lateral 

 bristles, surprisingly stout for such delicate flies: 

 humeral elements are 9 stiff hairs only; 3 (or rarely 1) 

 exceptionally long notopleural, 2 supraalar, and 1 

 postalar and 4 pairs of short, weak scutellar bristles, 

 those on scutellum rarely absent. Scutellum gently 

 convex, pubescent, apilose, and in the type of genus 

 and some species with 3 or 4 fine, short hairs. The 

 propleuron has an anteroventral tuft of stiff hairs, the 

 collar a band of scattered hair. Mesopleuron, sterno- 

 pleuron, pteropleuron, and hypopleuron apilose. Meta- 

 pleuron with 4 to 6 bristles; lateral metonotal slopes 

 micropubescent only ; lateral slopes of the metastemum 

 with pile; metastemum proper chitinized, with 5 to 10 

 long, fine hairs. Postmetacoxal area membranous; 

 tegula pubescent only. Prosternum dissociated. 



Legs : The legs are moderately stout, the hind femur 

 very slightly thickened distally; the pile of the legs 

 tends to be abundant, short and appressed dorsally, the 

 lower surfaces of the femora with very little pile. 

 Bristles are comparatively few and weak. The type of 

 genus bears the following complement of bristles : apex 

 of hind femur with 2 short, stout, pale, lateral apical 

 bristles, a single weaker apical medial bristle, a weak 

 ventral bristle near the base but rather long. Hind 

 lateral bristles beyond the middle, and 2 short bristles 

 on the basal half. Apex with 1 dorsal, 3 medial, 1 

 tibia with 3 or 4 weak, short, dorsal, 2 well developed 

 4 ventral bristles on the basal half, of which the more 

 basal 2 are quite long. This tibia bears long, strongly 

 lateral, 2 or 3 ventral bristles. Middle femur with 3 or 

 developed dorsal and ventral, oblique bristles which 

 consist of 3 dorsal, 4 or 5 ventral; the basal elements 

 are the longest and are at least half as long as the 

 tibia. End of midtibia medially with 1 exceptionally 

 stout, apical bristle which is straight and not recurved. 

 Anterior femur with long, more delicate, ventral basal 

 bristles, its tibia with 3 or 4 stout, posterior bristles; 

 the dorsal elements are 5 or 6 but are short and weak. 

 Apex with a distinct, ventrolateral, sharp, anteriorly 

 curved spine which is stoutly thickened at the base and 

 without corresponding basitarsal modification. Tarsi 

 end in sharp claws, well developed pulvilli and empo- 

 dium. Most if not all species have an anterior spur on 

 the posterior coxa. 



Wings: The wings are comparatively broad in the 

 type of genus, but more slender in other species. All 

 marginal and posterior cells open ; anterior branch of 

 the third vein ends immediately in front of the wing 

 apex, posterior branch immediately behind. Anal cell 

 closed in the margin in the type of genus, widely open in 

 most species. The second basal cell ends in 3 veins; 

 anterior crossvein is in the middle or just beyond the 

 middle of the discal cell. Alula short; ambient vein 

 complete. 



Abdomen : The abdomen is as wide as the mesonotum 

 with a tendency to be a little flattened and widened 

 through the middle where it is often fully as wide as 

 the thorax. Some species are a little more narrow with 

 parallel sides. Pile of the abdomen minute, scanty, 



