DASVPOGONINAE 



ROBBER FLIES OF THE WORLD 



81 



Metanotal callosity micropubescent only. Postero- 

 lateral metasternum and the narrow ventral metaster- 

 num densely pilose; postmetacoxal area membranous; 

 presternum dissociated. 



Legs : All the femora are swollen, especially the hind 

 femur, which in the middle is about 2y 2 times as thick 

 as its tibia. Pile of legs tine and appressed. The hind 

 femur and tibia have dense fringes of fine, erect, ventral 

 pile. Bristles are weak, the hind femur at most bears 



1 or 2 stiff hairs ventrally and 1 medially at the base. 

 This tibia has 2 weak bristles dorsolaterally along the 

 middle, 3 or 4 others dorsomedially and 2 more stout, 

 ventrolaterally on the apical third ; apex with 10 bris- 

 tles, most of them weak. Middle tibia with slightly 

 longer bristles and fine, long, stiff hairs posteriorly. 

 There is a conspicuous, long bristle anteriorly on the 

 outer third and a much smaller one at the middle, 

 and of the posterior elements 3 are moderately stout 

 and some 5 or 6 are mere hairs ; in addition there are 



2 long, slender, posteroventral bristles. Anterior tibia 

 quite similar to the middle pair, but only the posterior 

 elements may be considered to be bristles. The mid- 

 dle tibia anteriorly has a row of 4 slender bristles. 

 Apex of anterior tibia without spur. All basitarsi as 

 long as the next two segments. Claws slender, sharp; 

 the pulvilli long; the empodium half as long as the 

 claw. 



"Wings : The marginal cell quite widely open ; the an- 

 terior branch of the third vein arises gently; the an- 

 terior crossvein enters the discal cell a little before 

 the middle. All posterior cells and the anal cell widely 

 open; alula short and the ambient vein complete. 



Abdomen: The abdomen is comparatively robust, 

 but not quite as wide as the mesonotum. Males with 

 the first tergite widest; females with the third and 

 fourth tergites widest. Males with seven tergites, 

 the sixth is about half as long as the fifth and the sev- 

 enth half as long as the sixth. Females with eight 

 tergites, reduced in the same proportions. Both males 

 and females, but especially the males, show a deep, 

 transverse depression or groove on the second tergite 

 fully one- fourth of the distance from the base; this is 

 in contrast to other members of the tribe, where, if 

 present at all, it is quite basimarginal. Subbasal por- 

 tions of the next two tergites also with deep depression 

 but, nearer the base. Pile of abdomen fine and quite 

 appressed. Lateral pile on the second and third ter- 

 gites slightly longer and more erect, and still longer on 

 the first tergite where there are 7 pairs of quite weak 

 bristles. Bristles absent on the remaining segments. 

 Male terminalia rotate one-fourth to the left. The 

 epandrium is short but quite wide, with a short, lateral 

 lobe or process. Gonopod small, short, not at all prom- 

 inent. Hypandrium well developed with a small, lat- 

 eral process. Female terminalia very short and 

 inconspicuous and almost concealed by the seventh 

 tergite. 



Distribution: Nearctic: Bohartia bromleyi (1958). 



Genus Helolaphyctis Hermann 



Figubes 39, 536, 861, 870, 1676, 1878, 1929 



Helolaphyctis Hermann, Zool. Jahrb., vol. 43, p. 193, 1920. 

 Type of genus: Helolaphyctis modesta Hermann, 1920, by 

 original designation. 



These are medium size flies or smaller, belonging to 

 the Laphystini. They are characterized by the short 

 proboscis, cylindrical at the apex but compressed later- 

 ally in the middle. The ventrally gibbous face bears 

 numerous bristles. Also characterized by the short, 

 appressed pile of the mesonotum and abdomen and the 

 basally widened, second submarginal cell with the first 

 posterior cell open. From Apoxyria Schiner to which 

 it would appear closely related, it is separated by the 

 first four femora being normal, the hind pair only 

 slightly thickened, the hind tibia moderately thickened 

 and neither of these tibia or their femora arcuate. 

 Length 10 mm. 



Head, lateral aspect: The face is nearly plane with 

 the eye on fully the dorsal half ; on the lower portion is a 

 low, rounded, dorsally abrupt, ventrally retreating gib- 

 bosity. The eye is strongly convex anteriorly, plane 

 posteriorly throughout the greater middle portion and 

 rather strongly, though convexly recessive anteroven- 

 trally. The occiput is thick medially below the middle 

 but otherwise obliterated in profile. The pile of the oc- 

 ciput is long, fine and rather abundant ventrally, re- 

 placed by a prominent row of 16 bristles on the dorsal 

 half, with an extra row of shorter middle bristles. Dor- 

 sally the occiput is rather strongly excavated, leaving 

 the eyes reduced and rounded on their posterior medial 

 corners. Proboscis short, not extended beyond the face ; 

 the apex is bluntly truncate, cylindrical, the middle por- 

 tion laterally compressed, the ventral fissure prominent, 

 the base a little swollen both laterally and dorsally and 

 the medial ridge absent. The apex and the ventral sur- 

 face apically bear a fringe of stiff hairs ; the base ven- 

 trally has a few, quite long, fine hairs. Proboscis 

 directed obliquely downward. Palpus clearly of two 

 segments, both short, the first cylindrical and exca- 

 vated, the second swollen through the middle, not 

 porate and with several ventral and lateral long, sub- 

 apical, stiff, bristly hairs. 



Antenna attached at the upper third of the head and 

 moderately elongate. The first segment is slightly 

 longer than the second, convex and a little swollen 

 below; third segment attenuate on the basal fourth, 

 slightly compressed laterally, widened in the middle to 

 2y 2 times its basal width and bearing apically a quite 

 short microsegment which is a little longer ventrally, 

 dorsoapically oblique, and with an exposed subdorsal 

 spine. First segment with numerous, long, slender 

 bristles ventrally and laterally and at least 2 longer and 

 stouter, as long or longer than the combined length of 

 the first 2 segments; the dorsal setae stiff but shorter. 

 Second segment with 2 or 3 rather long, slender bristles 

 or stiff setae dorsally and ventrally, besides 1 or 2 

 shorter hairs. 



