1923] 
The Genus Cyrtopogon 
109 
35. Hypopleural pile black; hairs of hypopygium yellowish 
white; mystax white; abdomen of both sexes gray except 
front angles of segments; tibial bristles white except those 
at tips and on front side of first pair. (Cal.) . . rattus 0. S. 
Hypopleural pile white; hypopygial hairs black above; 
mystax white and black; anterior half of male abdominal 
segments shining; tibial bristles black, a few pale ones 
on extensor side of hind tibiae of female. (Wash.) 
coBsius. n, sp. 
36. Face convex below but not gibbous, facial pile dense and 
white; tibiae reddish at base; male abdomen broad, with 
sides and posterior margins pollinose, female abdomen 
narrow, anterior margins of segments 2-4 sometimes also 
pollinose. (Or., Wash.) (Proc. Cal. Acad. Sc. 1919, 
230) anomalus Cole. 
Face more gibbous, its pile largely or wholly black. . . 37 . 
37. Legs largely brownish red; geminate stripe of thorax dis- 
tinct and complete; pollen of abdomen confined to pos- 
terior and side margins of segments; style one-third the 
third antennal joint; scutellum without bristles; face and 
front brownish gray. (Ks., Col., N. M.) . . profusus 0. S. 
Legs black; scutellum with black bristles. (If scutellum 
with only marginal pile, see nugator female if facial 
hairs all black, or ccesius male if facial hairs white.) . . 38 . 
38. Abdominal fasciae extending along posterior edge of seg- 
ments; stripes of thorax very distinct. (Cal.) evidens 0. S. 
Abdominal fasciae extending along anterior margin of seg- 
ments 2-6 but not reaching sides, posterior angles with 
spots of white pollen; stripes of thorax indistinct; style 
one-tenth the third antennal joint. (Cal.) cerussatus 0. S. 
39. Legs in part reddish ; mystax black 40 . 
Legs black, rarely the knees alone brownish 41 . 
40. Hypopleural pile whitish; mystax rather sparse; wings 
hyaline; mesonotum largely gray. (Ariz.) . tibialis . Coq. 
Hypopleural pile black; mystax dense; wings brownish 
apically, crossveins clouded; mesonotum largely brown. 
(Or.) dubius Will. 
