DASTPOGONINAB 



ROBBER FLIES OP THE WORLD 



251 



and consist of 1 notopleural, 1 supraalar, 1 postalar, 

 and no scutellar bristles. Scutellar surface flat and 

 pollinose, apilose. Propleuron below with 8 or 9 long, 

 fine hairs, the pronotum with 4 pairs of stiff, long hairs, 

 the posterolateral section with 2 or 3 hairs. Upper 

 mesopleuron, its anterior extension and posterior mar- 

 gin each with 3 to 5 short, fine hairs. Pteropleuron and 

 hypopleuron without pile ; the latter has a long patch 

 spot of pubescence. Metapleuron with 8 to 10 long, 

 stiff hairs; metanotal slopes micropubescent only. 

 Sides of metasternum with 5 or 6 fine hairs, the meta- 

 sternum with short, fine, scattered pile; postmetacoxal 

 area membranous, but pollinose; tegula pubescent. 



Legs : All three pairs of legs are elongate and rather 

 slender. All legs with greatly reduced, scanty, fine 

 setate pile. The hind femur is slightly thickened dis- 

 tally; the bristles consist of a pair located dorsally a 

 short distance from the apex with an additional bristle 

 medially near the apex; also 3 short, stout, lateral 

 bristles on the basal half and 3 short medial bristles 

 on the basal half. Ventral surface with only 5 or 6 

 minute hairs. The hind tibia bears rather longer, quite 

 sharp bristles which consist of 4 to 5 lateral, 7 dorsal, 

 2 ventral, both beyond the middle ; apex with 1 dorsal, 

 1 medial, 2 lateral, and 3 ventral bristles. Middle femur 

 with 2 dorsal, 1 rather longer anterosubapical and 2 

 short, anterior bristles on the basal third ; its tibia bears 

 5 short dorsal, 6 anterior and an extremely long antero- 

 dorsal bristle at the outer third; ventrally there are 3 

 still longer, stout, oblique bristles. Anterior femur 

 with 1 anterior subapical and 1 or 2 weak posterior 

 bristles basally ; its tibia bears only short bristles, 6 or 7 

 anterior, 5 dorsal, 6 posterior elements. Apex of an- 

 terior tibia with 2 dorsal and 1 anterior bristle; ven- 

 trally it has a basally broad, expanded, very strong, 

 somewhat curved spine apposed against a flared, basal 

 expansion of the basitarsus. All tarsi end in well de- 

 veloped pulvilli, stout empodium half as long as the 

 sharp claws. 



Wings : The wings are somewhat more slender than 

 usual, subhyaline, the surface smooth. Marginal cell 

 widely open; anterior branch of third vein ends at 

 apex ; fourth posterior and anal cells closed and stalked ; 

 second basal cell ends in 3 veins. Alula of moderate 

 size ; ambient vein complete. 



Abdomen : The abdomen is elongate, slender, slightly 

 narrowed on the second and third tergites but in pro- 

 file concave and constricted at the base of the second 

 and third tergites and slightly on the fourth. The 

 abdomen is as long as the wings. First tergite is 

 scarcely swollen laterally ; eight tergites are present in 

 the female. Pile of abdomen exceedingly scanty, micro- 

 scopically fine, short and suberect, sides without longer 

 fringe of pile. Sides of first tergite with 2 small 

 bristles. Sternites with only a few scattered minute 

 hairs. Female terminalia short with a row of spines 

 on the acanthophorites ; the lateral process has 3 or 4 

 short, stout, bristly spines. No males seen. 



Distribution: Neotropical: Cyrtophrys attenuatus 

 Loew(1851). 



Genus Mirolestes Curran 

 Figures 71, 530, 1092, 1101, 1821, 1829 



Myolestes Bribes, Anal. Mus. Nae. Buenos Aires, ser. 3, vol. 

 4, p. 338, 1904. Preoccupied Aves, 1850. Type of genus: 

 Myolestes lynchii Brethes, 1904, by monotypy. 



Myiolestes Kertesz, Catalogus dipteroruni . . ., 1909, emenda- 

 tion. 



Mirolestes Curran, Amer. Mus. Novitates, no. 806, p 1, 1935, 

 change of name. 



Elongate, slender flies of extremely bare aspect with 

 very little pile. The abdomen is slightly spatulate or 

 clavate. In many respects they are strikingly similar 

 to Neolaparus Williston to which perhaps they are re- 

 lated. They are best recognized by the slender form, 

 the long cervix, the short, wide head, the virtual ab- 

 sence of pile on the face with bristles restricted to the 

 epistomal margin. The subepistomal region is long 

 and slightly oblique. Ocellar bristles are reduced to 

 the postvertex. Length 15 to 18 nun. 



Head, lateral aspect : The face in profile is short above 

 and becomes gradually a little more prominent at the 

 epistomal margin; the whole face is nearly plane, or 

 with a very slight concavity on the lower portion. Eye 

 short, plane in posterior profile except ventrally and 

 at the vertex with slight anterior recession ventrally. 

 The occiput, however, is prominent, especially towards 

 the middle of the head and below. The very long cer- 

 vix allows it to be freely inspected in every part of it. 

 Occipital pile is fine, long and scanty, and extending 

 in scattered fashion over the lower half; above the 

 middle there are a few weak bristles, subappressed 

 and short, 5 or 6 in number, but behind the ocelli, 

 rather deeply placed, there is a pair of long, stout, 

 sharp bristles. The proboscis tends to be directed 

 nearly straight downward, is strongly compressed 

 laterally and in profile bluntly and obtusely rounded 

 with a conspicuous medial ridge dorsally on the basal 

 half. The proboscis is a little widened laterally to- 

 wards the base, bears a few, fine hairs at the apex 

 and below and a few long hairs ventrally at the base. 

 The palpus is clearly of two segments, the first seg- 

 ment excavated, the second porate, clavate, cylindrical 

 with numerous, stiff bristles ventrally, laterally and at 

 the apex. The antenna is attached at the upper third 

 of the head. It is moderately long and slender, ap- 

 proximately as long as the head, the first two segments 

 equal; the third is a little longer than the first two, 

 laterally compressed, and bears dorsally and medially 

 a short, subapical spine. The pile of the first two seg- 

 ments consists of numerous, subappressed, dorsal and 

 ventral bristly hairs, which become weak bristles on the 

 second segment. Third segment with 8 oblique setae 

 dorsally. 



Head, anterior aspect: The face below antenna is 

 less than one-third of the head width and has nearly 

 parallel sides, at most slightly divergent below. Sub- 

 epistomal area unusually long, subvertical, nearly plane 

 and bare. The face is densely micropubescent with 

 about 12 fine hairs on each side on the lower portion of 



