DAS1P0G0NINAB 



ROBBER FLIES OF THE WORLD 



153 



pile is similar with bristles absent. The occiput is 

 short dorsally becoming extensive below. The pro- 

 boscis is quite short, stout, swollen towards the base, 

 the apex bluntly pointed; it is also swollen basally in 

 dorsal aspect ; it bears a low, medial ridge and numer- 

 ous, long, delicate, ventral hairs on the basal half. 

 It is directly chiefly forwai-d and only slightly oblique 

 and does not extend beyond the face. Palpus minute, 

 cylindrical, closely appressed against the medioventral 

 aspect of the cheek and bearing numerous, long, bristly 

 hairs ventrally and near the apex. First segment 

 short, more or less fused to cheek; second segment 

 longer and slender, without pore. The antenna is at- 

 tached at or near the middle of the head, its length 

 is moderate and quite slender; the first two segments 

 are slender and the first is a little longer than the 

 second. Third segment not quite twice as long as the 

 first two combined ; it is more narrow than the second 

 segment, strongly constricted on the basal half of the 

 segment and dilated distally to more than three times 

 its basal width, then rather abruptly narrowed at the 

 apex; it bears apically a stout microsegment, antero- 

 dorsally truncate and carries an apical central spine. 

 First and second segments with numerous, long, fine, 

 bristly hairs except medially. 



Head, anterior aspect : The face below the antenna is 

 about one- fourth the width of the head. Subepistomal 

 urea short, horizontal, concave and pubescent. Face 

 densely micropubescent; almost entirely covered, except 

 immediately beneath the antenna, with numerous, long, 

 slender bristles. Across the epistoma and continued 

 down the whole lateral margin there is a band of long, 

 bristly hairs; upper face without bristles. Front 

 large, long, wide, slightly raised laterally with 3 

 rows of long, slender, bristly hairs. Vertex but little 

 excavated with gently sloping sides; a crease sets off 

 the large, rather low ocellarium and continues shal- 

 lowly down the front, dividing it into 3 parts. The 

 ocellarium bears large ocelli, 3 pairs of long, slender, 

 bristly hairs between the ocelli, 2 pairs between the 

 posterior ocelli and 4 pairs behind. Anterior facets 

 enlarged. 



Thorax: The thorax is every where pollinose; the 

 pile of the mesonotum is abundant, quite long, fine, 

 bristly and erect with similar bristles medially but 

 poorly differentiated. Dorsocentral bristles poorly 

 differentiated anteriorly with 4 long, more stout ele- 

 ments in front of the suture and 5 pairs posteriorly. 

 Humerus with long, bristly pile. The following com- 

 plement of long, but slender bristles is present laterally : 

 3 notopleural, more or less transversely, 3 supra alar, a 

 tuft of 8 postalar and along the scutellar margin 5 pairs 

 with several additional submarginal pairs of bristles 

 which are more slender. Scutellum thick, convex, 

 though with a tendency to be flattened on the basal 

 third, the whole micropubescent. Propleuron densely, 

 long, fine pilose with similar, slightly bristly pile on the 

 anterior collar; the dense, fine pile continued on the 

 posterolateral pronotum; bristles absent. Mesopleuron 

 with a tuft of long, bristly pile posterodorsally, anterior 



and middle stemopleuron with long, fine pile; ptero- 

 pleuron and hypopleuron apilose. Metapleuron with a 

 wide band of some 20 long, slender bristles. Lateral 

 slopes of the metanotum micropubescent only ; the lat- 

 eral metasternum and the ventral metasterniun with 

 some long, fine pile; postmetacoxal area membranous; 

 tegula with setae. Prosternum fully dissociated. 



Legs: The femora are stout without being swollen 

 and bear fine, scanty, short, appressed pile dorsally with 

 numerous, long, fine hairs medially, laterally and ven- 

 trally and with a ventromedial fringe of still longer 

 bristly hairs. Hind tibia with a fringe of long, fine, 

 erect pile and appressed, dense setae only at the imme- 

 diate apex. The following complement of bristles pres- 

 ent : on the hind femur a stout, long, lateral bristle at 

 the apical third ; its tibia has long, bristly hairs medially 

 on the basal half, 7 similar elements dorsomedially of 

 which the last 2 stand out as slender bristles; also 8 

 dorsolateral bristles of which 2 near the middle and at 

 the outer fourth are rather conspicuous bristles. Above 

 them lies a fringe of 8 or more long, bristly hairs; ven- 

 trolaterally there are 2 stout bristles on the distal half 

 with 2 similar ventromedial bristles equally long and 

 stout; apex with 3 long, stout, ventral bristles and a 

 similar medial bristle. Middle femur with a stout, an- 

 terior bristle at the apical third and dense, long, fine 

 pile on all sides except dorsally. Middle tibia with 2 

 long, stout anterodorsal bristles, a long posterodorsal 

 fringe and a double posteroventral fringe of bristly 

 hairs. Ventrally there is 1 long distal and 1 long, 

 stout posteroventral bristle. Anterior femur with only 

 long, fine pile on all sides except anterodorsally ; its 

 tibia has 3 or 4 short bristles anterodorsally, 2 long, 

 stout bristles posteriorly, with several rows of bristly 

 hairs dorsally and posteriorly. This tibia is without 

 spine. The tarsi end in sharp claws, long pulvilli and 

 an especially long, strongly compressed empodium not 

 swollen at the base. 



"Wings : The marginal cell is widely open, the fourth 

 posterior cell slightly narrowed ; the upper end vein of 

 the discal cell is a little shorter than the lower vein and 

 rectangular to the first posterior cell. Middle end vein 

 of the second basal cell quite short; the anterior cross- 

 vein enters the discal cell at the middle. The anal cell 

 is widely open, the alula is twice as wide as the costal 

 cell ; ambient vein complete. 



Abdomen: The abdomen reaches to the end of the 

 wing; it is cylindroid and tapered but broad at the 

 base and nearly as wide as the mesonotum. The pile of 

 the abdomen is abundant, short and fine, erect on the 

 terminal segments, longer along the sides of the ter- 

 gites; first tergite laterally with 4 pairs of long, slender 

 bristles. Males with seven tergites, the seventh only 

 half as long as the eighth and shorter laterally. There 

 is a very narrow dorsal trace of the eighth tergite. 

 Females with eight tergites, the eighth is as long as the 

 seventh. Male terminalia fully rotate, large and con- 

 spicuous and obtuse and dominated by the epandrium. 

 Epandrium cleft to the base, apposed except distally 

 where it is narrowly divergent, enclosing the proctiger. 



