LAPHR1INAE 



ROBBER FLIES OF THE WORLD 



403 



cavated and carries a stout, short spine. First antennal 

 segment with 1 or 2 minute setae dorsally and a single, 

 ventral, rather stout, long bristle ; second segment with 

 a similar, only slightly shorter ventral bristle, 3 short, 

 fine setae, and several other setae dorsally. 



Head, anterior aspect : The face below the antenna is 

 a fourth the head width and even more narrowed across 

 the middle and slightly divergent below. Face coarsely 

 pubescent, with 1 or 2 pairs of long, slender, down- 

 wardly curved bristles on the upper portion of the face 

 shortly beneath the antenna. On either side below and 

 above the longer ventral bristles are 3 or 4 additional 

 pairs of somewhat shorter, more slender bristles or 

 bristly hairs also curled downward. The low, ventral, 

 convex protuberance of the face bears a rather close-set, 

 rectangular patch of numerous, long, comparatively 

 slender bristles ; these also extend down along the sides 

 of the subepistoma. Front short and pollinose, with a 

 deep, longitudinal fissure or groove running from the 

 antenna to behind the ocellarium. The width of the 

 front is the same as the lower face but is doubled at the 

 level of the posterior eye corners. The lateral eye mar- 

 gins have 3 distinct, moderately long, comparatively 

 stout bristles; the vertex is moderately excavated, the 

 ocellarium large, with steeply sloping sides, and bear- 

 ing between the ocelli a pair of long, stout bristles. An- 

 terior eye facets moderately enlarged. 



Thorax : The mesonotum. is shining and not pubescent, 

 except narrowly behind the humerus. The pleuron is 

 densely appressed pubescent, except on the posterior 

 mesopleuron, where a large triangular area is bare. 

 Pile of mesonotum short, flat appressed or curled and 

 setate, the surface of the mesonotum and upper meso- 

 pleuron is coarsely punctate ; the following complement 

 of bristles is present laterally: a single, long, rather 

 stout notopleural, 1 supraalar, 1 postalar, and 2 pairs 

 of scutellar bristles. Scutellum rather thick and convex 

 with impressed margin, base with a deep crease; the 

 surface is covered with abundant, short, curled, ap- 

 pressed pile and with coarse punctures. Propleuron 

 with short, stiff pile ventrally and on the pronotum; 

 pile absent on the middle posterior portion. Anterior 

 sternopleuron with some long, stiff, bristly hairs. Up- 

 per posterior corner bears a single, long, conspicuous, 

 slender bristle. Pteropleuron, hypopleuron apilose; 

 metapleuron with a vertical row of 5 or 6 long, slender 

 bristles; lateral slopes of the metanotum with 3 or more, 

 exceptionally stout, spinous bristles. Lateral slopes of 

 the metasternum with pile, ventral metasternum com- 

 posed of 1 narrow, widely isolated, thin strip of chitin. 

 The large anterior membranous portion has 3 or 4 fine, 

 long hairs; the postmetacoxal area forms a short, but 

 complete, arched band of chitin. Squama extremely 

 short and apparently without fringe. 



Legs: All the femora are stout and more or less 

 swollen ; the hind femur is rather short and strongly 

 swollen distally and narrowly spindly at the base; the 

 hind tibia is moderately stout and distinctly arcuate. 

 The pile of the femur dorsally consists of moderately 



abundant, appressed, setate pile; the ventral surface 

 of the hind femur has a rather dense fringe of extremely 

 fine, erect pile which is chiefly confined to the medial 

 half and with near the base 1 or 2 much longer, slender, 

 bristly hairs, one of which is nearly half as long as the 

 femur. Ventral surface of the hind tibia with a some- 

 what more abundant fringe of fine, erect pile and no 

 brush of setae; its medial surface has a few, appressed 

 setae only at the extreme apex. The hind femur has at 

 the apex 1 slender, dorsomedial and similar dorsoapical 

 bristles and 1 lateral beyond the middle on the most 

 swollen part; hind tibia with long but exceptionally 

 slender bristles consisting of 2 dorsomedial on the outer 

 half, 2 dorsolateral at the basal and distal third, and 

 2 or 3 long, slender, ventral, bristly hairs. Middle 

 femur with comparable apical dorsomedial and dorso- 

 lateral bristles; this tibia with longer, stouter bristles 

 consisting of 3 anterodorsal and 2 or 3 posterodorsal ami 

 2 or 3 posteroventral bristles besides 2 distal bristles. 



Anterior femur with long, slender hairs ventrally, 

 similar to the long, ventral hairs on the middle femur; 

 also with an apical posterodorsal bristle and weaker 

 anterior bristle. Anterior tibia with 3 short, slender 

 anterodorsal, 2 or 3 posterodorsal, 2 or 3 quite long, 

 slender posteroventral, and 4 or 5 long, ventral bristles. 

 Tarsi are comparatively short; the first two segments 

 are rather stout ; the first is nearly as long as the next 

 two; the tarsi end in long slender, sharp claws, well 

 developed pulvilli and long bristlelike empodium only 

 a little swollen at the base. 



"Wings : The marginal cell is closed with a very short 

 stalk, the end of this cell wide and abruptly arched. 

 The anterior branch of the third vein ends at or im- 

 mediately above the wing apex; the posterior branch 

 a considerable distance behind the wing apex; second 

 submarginal cell rather strongly arched basally, the 

 cell flared and wide apically. First posterior cell 

 widely open; fourth posterior cell closed with com- 

 paratively long stalk ; end vein of the fourth posterior 

 cell and of the discal cell very nearly aligned, offset by 

 a distance equal to a fourth the width of the discal cell. 

 Anal cell narrowly open. Alula absent or extremely 

 narrow and without fringe. Ambient vein ends at the 

 base of the alula. The anterior crossvein enters the dis- 

 cal cell a little beyond the middle. 



Abdomen: The abdomen is nearly as wide as the 

 thorax and slightly flattened; it is only gently convex 

 across the middles of the tergites, the lateral area more 

 strongly convex; abdomen strongly punctulate. Seven 

 tergites are present in the male ; the seventh is nearly 

 if not quite as long as the sixth and tends to be only 

 slightly curved down or cuplike, and is without pos- 

 terior, crimped margin, or rim. In profile the first 

 three or four tergites are each somewhat convex; the 

 lateral margins also convex with the incisures indented. 

 Pile of the abdomen minute but abundant, appressed 

 and setate; sides of all of the tergites with a single, 

 moderately long, distinct though not very stout bristle. 

 The male terminalia are large though considerably 



