DASTPOGONJNAB 



ROBBER FLIES OF THE WORLD 



159 



fine, long hairs posteriorly and no bristles. Ptero- 

 pleuron with a single long, stout, dorsal, black bristle. 

 Hypopleuron without pile, metapleuron convex with a 

 narrow band of moderately long, black bristles, some 

 12 altogether. Slopes of the metanotum with 8 or 9 

 stout, black bristles. 



Legs: The hind femur is of moderate thickness, 

 rather elongate with dense, subappressed, stiff, black 

 pile and with a row of 7 stout, moderately long, black 

 bristles along the lateral surface but no dorsal bristles 

 at the apex. Hind tibia elongate, slender, with 5 stout, 

 short, black, lateral bristles, 5 dorsal, 5 ventrolateral, 

 and in addition 4 ventromedial bristles. Apex with 

 spinous bristles as follows : 2 lateral, 2 dorsal, 5 ventral, 

 and 2 medial bristles. Middle femur with a row of 4 

 anterior bristles; its tibia with 4 anteroventral and 5 

 anterodorsal, 4 dorsal, 5 posterodorsal, 5 posteroventral 

 bristles. Apex with 2 dorsal, 2 anterior, 2 posterior, 

 and 1 ventral bristle. Anterior femora with 2 weak, 

 black, anterior bristles near the middle; its tibia has a 

 series of short, spinelike bristles which consist of 5 

 anterodorsal, 5 posterodorsal, and 5 posteroventral 

 spines, all of which are short but stout. Apex with 2 

 dorsal, 1 anterior, 2 ventral, and 1 posterior spinelike 

 bristle. Apex otherwise unmodified and without any 

 protibial spine. The claws are sharp, pulvilli four- 

 fifths as long as the claws. The middle claw more 

 strongly arched ; empodia slender, nearly as long as the 

 pulvilli. 



"Wings: The venation is similar to Microstylum in 

 most features. The first posterior cell is open but much 

 narrowed at the margin. The second posterior cell has 

 a short stalk or petiole at the base, separating it from 

 the discal cell. Ambient vein complete; alula well 

 developed. Color dark sepia brown throughout, 

 scarcely lighter posteriorly behind the third vein. 



Abdomen: The abdomen is a little longer than the 

 wing, subcylindrical and tapering. The lateral margin 

 of the first segment bears 8 stout, black bristles; re- 

 maining segments without bristles and only fine, sub- 

 appressed pile. 



Subgenus Eclipsis Bezzi 



Figures 494, 950, 959, 1754, 1861 



Eclipsis Bezzi, Ann. Soe. Ent. Belgique, vol. 52, p. 375, 1908. 

 Type of subgenus : Eclipsis maculiventris Bezzi, 1908, by 

 monotypy. 



The second posterior cell is closed and petiolate. 

 This character, together with strong macrochaetae, 

 prominent ocellarium and the ending of the costa 

 shortly past the anterior branch of the third vein were 

 used by Bezzi to distinguish this fly based only on one 

 species from Microstylum Macquart. The character- 

 ization must be considered extremely weak. In all of 

 the many species I have examined, the costa ends just 

 past the first branch of the third vein. In respect to 

 the second posterior cell species vary widely from those 

 with closed or open cell, with or without petiole, and 



535914— 62— pt. 1 12 



are commonly with a distinct vein of varying length 

 between the medial posterior crossvein and the upper 

 end of the fourth vein (section one of the intercalary 

 vein). The macrochaetae on the humerus may form a 

 better basis of separation. In any case, I regard it as 

 a weakly based subgenus of Microstylum. Length 

 23 mm. 



Head, lateral aspect: The face is short but more 

 prominent below. Occiput with long, bushy pile ; near 

 the middle there is a sublateral row of 12 or more rather 

 long and quite stout pale bristles. Proboscis long, 

 strongly compressed laterally, attenuate, the apex nar- 

 row and bluntly rounded. Palpus elongate, greatly 

 flattened, the basal section very short, the entire palpus 

 with long, stiff bristles and four apical bristles of 

 great strength and moderate length. 



Head, anterior aspect: There is a strong, circular 

 mystax of long, stout, downwardly curved, pale 

 bristles in 2 rows with shorter bristles immediately 

 above. Upper portion of the face is bare of pile but 

 everywhere pubescent. The face across the middle is 

 one-fifth the total head width, slightly divergent be- 

 low. Sides of the front with 3 extremely stout, long, 

 black bristles and below them 6 or 7 long, bristly, pale 

 hairs. The vertex is but little excavated and little 

 widened, the ocellar protuberance extremely low and 

 bearing 5 or 6 long, slender, yellow hairs. 



Thorax: The mesonotum uniformly suberect, stiff 

 pilose, the pile a little longer on the anterior margin, 

 which is somewhat raised and abrupt. The mesonotum 

 otherwise is only gently convex. Pronotum with 8 or 

 more pairs of stiff, bristly hairs. Humerus with 5 ex- 

 tremely stout, long, black bristles. Notopleuron with 7 

 extremely long, stout, black bristles and with 4 other 

 shorter bristles. Supraalar region with 4 stout, long 

 bristles; postalar with 2; the scutellar margin with 2 

 pairs and the prescutellar region with a double row of 



3 or 4 bristles, all of which are long and stout ; upper 

 posterior mesopleuron with 2; pteropleuron with 1; 

 metapleuron with a cluster of 20 or more bristles. The 

 lateral slopes of the metanotum have a transverse, dou- 

 ble row containing 16 bristles ; hypopleuron with none. 

 Laterally the propleuron on each side bears a single 

 immensely stout, long, black bristle. Pleuron pubes- 

 cent; mesopleuron with scattered pile; hypopleuron 

 with a few, long, slender hairs. 



Legs : Hind femur stout but not thickened ; it bears 

 abundant, appressed, fine, short, setate pile dorsally, 

 laterally and ventrally. It also bears 4 stout, short, 

 black bristles along the middle of the lateral margin 

 but none dorsally at the apex. Tibia of uniform width, 

 slender, the bristles short but stout ; there are 5 dorsal, 



4 dorsolateral, 5 ventrolateral and at the apex 2 dorsal, 

 1 lateral, 2 ventral, 2 medial bristles. Middle femur 

 with 2 stout, anterior bristles at middle and outer third 

 and 1 on the basal third and 1 posteriorly at the outer 

 fifth. The middle tibia has short bristles as follows : 5 

 dorsal, 4 anterodorsal with the middle two much longer, 

 4 anterior, 7 posterior, 4 posteroventral, and 4 antero- 



