104 NKAV NOKTIl AMERICAN ANTilOMYIIDAE (dIPTEEa) 



seen from above; antennae, palpi and proboscis black. Thorax not vitiate, 

 the dorsum with brownish pruinescence. Abdomen without dorsal mark- 

 ings. Legs yellow, mid and hind coxae gray; tarsi of mid and hind legs 

 hirgely fuscous. Wings (^Icar, veins brown, yellow basally. Calyptrae white. 

 Halteres yellow. 



Head a little higher than broad in front; froiis shghtly less than onc-thirfl 

 of the head-width at vertex, a little narrowed anteriorly; each orbit about 

 half as wide as interfrontalia, with four bristles and a few hairs; parafacial 

 almost linear; antennae extending nearly to the mouth, third joint angulate 

 at apex; arista almost bare; one or two setulac above vibrissac. Acrostichal 

 setulae in two rows; lower stigmatal bristle directed downward; scutellum 

 with two long lateral l)ristl(>s. Abdomen slender, cylindrical, slightly com- 

 pressed apically; hypopygium and fifth stcrnite small (fig. 50). Legs willi 

 the normal number of bristles, which are of moderate length and strength; 

 hind tarsus not much longer than its tibia, the basal joint less than half as 

 long as tibia. Wings a little more than twice as long as wide, rounded apic- 

 ally; costa with fine setulae which are distinctly longer than the diameter 

 of the costal vein; last section of fourth vein about 2.25 as long as the pre- 

 ceding; veins three and four slightly arcuate, almost parallel apically. 



Fenuik.— Differs from the male in having the fore coxae and all femora 

 largely fuscous. 



Length, 3 nun. 



Type.— d^; Grant, Colorado, July 21, 191(3, (E. C. Jackson). 

 Allotype.— 9 ; Farewell Creek, Saskatchewan, Canada, July, 1907. 



A female from Montana has the apical scutellar l)ristles present 

 but weak. 



Type in collection of U. 8. Bureau of Biological Survey. 



Coenosia denticornis sj). n. 



Fcinnlc. — Paler in color than dichaela, the frons grayish pruinescent wIkmi 

 viewed from above and with the anterior margin rufous yellow. Legs yellow . 

 all coxae and fore femora largely fuscous; tarsi black. 



Head as broad as high; frons parallel-sided, a little over one-third as wide 

 as head, each orbit less t-liaii half as wide as interfrontalia, with three l)ristles; 

 antennae not extending to mouth, third jdint thorn-like nt apex on upper 

 side; arista pubescent (fig. 41). 44iora('ic (^haelotaxy as in dichaela. Costal 

 setulae not as long as diamett^r of costal vein. Length, 2.5 mm. 



Tijpc. — 9 ; Farew(>ll Cre(4'C, SaskatclK^van, Canada, July, 1907, 

 [Illinois]. 



This species most nearly ivsvmhlcs Jhti'i pes ^Unn (nee Willislon), 

 hut the third anlemial joint is very diCfercMitly shajied at ai)ex in 

 the latter. 



