217 



The revision presented herewith inckides all the North American 

 forms known to me as having been referred to Palpomyia and 

 Scrrouiyia. 



Revision of Species 



1. Yellow species; apices of fore femora narrowly and of the hind 



pairs broadly blackened. Fore femora thickened ; posterior tibia 

 brownish, with a broad sub-basal ring and the apices black; last 

 tarsal joint without spines on the ventral surface. Fore femora 



with bhick spines; tarsal claws minute, subequal. (Pa.) 



rufa Loew. 



I have not seen this species, which may really belong to the 

 genus Heteromyia. 



— Black or brownish black species, sometimes with very distinct 



pollinosity 2 



2. AVings with a distinct spot or ])and. Last tarsal joint unarmed. 



(Fla.) nuhifera Coquillett. 



— AVings without a distinct spot 3 



3. Last tarsal joint without two rows of ventral spines 4 



— Last tarsal joint with two distinct rows of ventral spines 9 



4. Knob of halteres black; shining black species with minute subequal 



tarsal claws. Legs fuscous, the bases of the femora, the fore tibia, 

 and the bases of all the tarsi yellowish. The fore femora are not 

 thickened and have spines, while the mid and hind pairs are 



unarmed trivialis Loew. 



Described from examples obtained at Washington, D. C. I 

 have not seen the species, though the male which I assign to 

 suhasper in a subsequent part of this paper agrees very 

 closely with the rather brief description given by Loew for 

 irivialis. (See note under subasjjcr, p. 223.) 



— Knob of halteres yellow, or if black the species is not shining black 



in color ; claws at least moderate in size 5 



5. Hind femora very much thickened, the fore and mid pairs normal. .6 



— Hind femora not conspicuously thickened 7 



6. The claws of the hind tarsi very unequal in length, the outer one 



at least four times as long as the inner femoraia Meigen. 



This common European species has been recorded by Coquillett 

 as occurring in Alaska. I have not seen the specimens upon 

 which the record is based, so can not say if they belong to 

 this species. 



— The claws of the hind tarsi subccpial in length. 



Female. — Black, shining. Antennte, face, palpi, and legs 

 brownish yellow. Halteres yelloAv. Wings grayish, veins 

 brown. 



Eyes narrowly separated ; antenna reaching to base of abdomen, 

 the joints rather distinctly haired, apical five not much 

 elongated ; proboscis very distinctly protruding, about two 



