122 



UNITED STATES NATIONAL MUSEUM BULLETIN 2 24 



the gibbosity is confined to the lower half of the face, not 



extending to the antenna 66a 



66a. Face extensively produced and gibbous. Densely long, fine 



pilose flies 67 



Face short but distinctly convex ; if produced, the swelling 

 is developed ventrally and not extending to the upper 

 face 70 



67. Costal cell on the outer half greatly narrowed. Abdomen 



compressed laterally. Males with hamate process at base 

 of anterior femur ; mesonotum with a mane. 



TOBEMTIA Hull 

 Anterior margin of wing normal. Abdomen never com- 

 pressed laterally. Processes absent 68 



68. Third vein of wing branched before or opposite discal cross- 



vein ; anterior erossvein situated well beyond the middle 

 of the discal cell. Third antennal segment broadest 

 basally, tapering apically. Scutellum with fine, discal 

 pile ; margin with numerous, long bristles. Densely pilose 

 flies. Middle tibia at apex with a pair of contrastingly 

 stout, isolated bristles, 1 element of the pair often 



black Eucyrtopogon Curran 



Third vein branched well beyond the discal erossvein; an- 

 terior erossvein usually at or before the middle of the 

 discal cell, rarely placed slightly beyond the middle of this 

 cell. Third antennal segment generally broadest at or 

 beyond the middle. Scutellum pilose on base, with strong, 

 short, marginal bristles 69 



69. Scutellum bare, with short, strong, marginal bristles. Dor- 



socentral bristles usually present. Comparatively bare, 

 small flies with abdomen in part pollinose and the face 

 less conspicuously and only moderately produced. Middle 

 tibia at apex ventrally with 5 stout bristles. 



Nannocyrtopogon Wilcox and Martin 



Scutellum with long pile and sometimes a few, apical 



bristles intermixed. Dorsocentral bristles absent. Ter- 



gites usually with pollinose bands. Flies of extensive, 



long, comparatively dense pile . . . Cyrtopogon Loew 



70. Face short throughout. Face and vertex with fine pile only ; 



bristles absent. Apex of middle tibia with a stout, 

 straight, spinous bristle. Small, slender flies with narrow, 

 cylindroid abdomen ; comparatively bare flies, the abdo- 

 men with pollinose markings 71 



Face with stout bristles or if absent, the middle tibia lacks 

 a distinct, segregated spine 72 



71. Face with dense, fine pile of distinctly bristly character. 



First and second antennal segments each with 1 or 2 

 pairs of characteristic, long, stout, but blunt bristles. 

 Mesonotum with fine, rather long, erect pilfi. 



Backomyia Wilcox and Martin 



Face with loose, fine pile. Basal antennal segments with 



only fine, normal, curved, bristly hairs. Mesonotum with 



fine, long, distinct, dorsocentral bristles . Wllcoxia James 



72. Mesonotiun rather strongly humped; face usually gently 



convex, with much flue pile and a few scattered bristles ; 

 very small, dark flies and usually fine, long, densely 

 pilose. Hind metatarsus distinctly enlarged and swollen, 

 at least contrastingly stout and robust. Hind tibia usu- 

 ally distally swollen also. Flies of 5 or 6 mm. length, 

 more rarely 8 to 10 mm Holopogon Loew 



Flies without swollen, posterior basitarsus 73 



73. Eye exceptionally narrow above and below. Abdomen 



moderately elongate but broad and more or less flattened, 

 and basally nearly as wide as the mesonotum ; lateral 

 margins of abdomen densely pilose, the middles of tergites 

 often quite bare, with greatly reduced pile. 



Pycnopogon Loew 



Eye of normal length above and below. Abdomen more 



slender without conspicuous, lateral fringes of pile . 74 



74. Third antennal segment and its style or microsegment un- 



usually slender and regularly attenuate from the base of 



the segment 75 



Third antennal segment of nearly the same width through- 

 out or slightly narrowed distally 76 



75. Second antennal segment less than half as long as the third 



segment; microsegment or style long and pointed. Face 



wide Heteropogon Loew 



Second antennal segment longer ; style short and less pointed. 

 Face more narrow and quite plane, the pile loose and weak. 

 Abdomen narrow with fine pile ; quite small flies. 



Anisopogon Loew 



76. Mesonotum high, strongly arched with numerous, conspicu- 



ous, long, stout, dorsocentral and shorter, fine acrostical 

 bristles present. Third vein (usually) branched before 

 the discal erossvein and with a distinct stump vein ; base 

 of second submarginal cell subtruncate or rectangular. 

 Face wider, bristles weak, situated chiefly below. Vertex 

 with 2 pairs of long, stout bristles. All femora slender, 

 the hind pair with only a medioapical tuft of bristles. 



Metapogon Coquillett 

 Mesonotum of normal height and moderately convex. Third 

 vein branched beyond the discal erossvein. Face with 

 numerous, exceptionally stout bristles. Face pile gener- 

 ally absent ; third antennal segment robust. 



Coleomyia Wilcox and Martin 



77. Face with numerous, stout bristles ; pile absent ; face becomes 



more prominent toward the epistoma. Occiput undevel- 

 oped dorsally Coleomyia Wilcox and Martin 



Face with numerous, long, stiff hairs and slender bristles or 



the occiput tumid above 78 



7S. Occiput expanded and swollen dorsally, thick and prominent 

 throughout the posterior portion of head ; face usually with 

 numerous, long bristles ; palpus large, swollen ; proboscis 

 pointed at apex Hadropogon Loew 



Occiput undeveloped above ; palpus small ; proboscis usually 

 robust but short and bluntly pointed, or rounded at apex. 

 Usually small, short, pollinose-marked flies, but occa- 

 sionally long and slender 79 



79. Short, obtuse, small flies with partly pollinose, partly bare 

 head, thorax and abdomen. Whole face more or less 

 pilose with more bristly pile below. Anal cell closed or 

 closed in the margin. Tarsal segments short, their bristles 

 conspicuous but short . . . Amphisbetetus Hermann 



Long and rather slender, black flies wholly covered with 

 pale whitish pollen. Only the lower half of face with 

 bristles and pile. Anal cell widely open. Tarsal seg- 

 ments quite long, their bristles long and conspicuous 



Graptostyxus, new genus 



Genus Stenopogon Loew 



Figures 126, 447, 449, 894, 901, 903, 910, 1775, 1817, 1938 



8teno}>offon Loew, Linnaea Entomologica, vol. 2, p. 453, 1847. 

 Type of genus: Asilus sabaudus Fabricius, 1794. Desig- 

 nated by Coquillett, 1910, the last of six species. 



Flies of basally stout, elongate, tapered abdomen, in 

 which the pile is reduced and the bristles are numerous 



and strong. They are largely short pilose and bare in 

 appearance. The head from the frontal aspect is cir- 

 cular, the metapleuron is micropubescent only. This is 

 the only firm character separating the members of the 

 genus from Scleropogon Loew ; in that genus the meta- 

 pleuron has some long pile or bristles, usually in abund- 

 ance. The third antennal segment, the microsegment 

 excluded, rarely reaches twice the length of the first 

 two segments. Anterior tibia without spine. Male 



