Vol. XI] CURRAN— REVISION OF THE PIPIZA GROUP 373 



No. 870, Mus. Calif. Acad. Sci., Jordan, Ont., June 15, 

 1919, H. Curran, collector. 

 Type locality, Guelph, Ontario. 



35. Cnemodon trochanterata Malloch (Figs. 96, 97, 98, 99) 

 Malloch, Proc. Ent. Soc, Wash., XX, p. 127, 1918. 

 Habitat: Illinois! Pile mostly tawny; posterior ven- 

 tral tubercle large; wings clouded with luteous brown; 

 hind trochanteral spur small. 



Male: Length, 7 mm. Antennae brownish, second and third joint basally, 

 below, yellowish; third joint twice as long as broad, less rounded below; face 

 and front shining bluish black, light yellowish pilose, above the antenna? and 

 the front of the vertical triangle with blackish pile. In profile the face is re- 

 ceding, slightly rounded above; eyes brownish pilose; occipital cilia yellowish, 

 the lateral hairs black. Thorax and scutellum aeneous black, the latter slightly 

 bluish at the apex; pile tawny, on the pleura' lighter. Abdomen opaque black, 

 first segment and the usual areas shining, metallic; pile tawny, the usual areas 

 with shorter black pile; hypopygium black pilose; venter of third segment 

 carinate, the middle of the carina flattened and transversely rugose; basal 

 spur on fourth segment conspicuous, the process on apical third large, tuber- 

 culate. Femora black, tips yellowish; tibise and tarsi yellowish; middle 

 tibia? with broad band beyond the middle and hind tibia? except the broad 

 base and end, blackish; front tibiae posteriorly blackish beyond the middle; 

 last one or two joints of all the tarsi brownish, the hind basitarsi obscurely 

 brownish; middle tibia? slightly produced anteriorly; middle coxal process 

 slender, short, not very conspicuous; hind coxal spur small, not conspicuous; 

 hind trochanteral process slender, over twice as long as thick, luteous, its base 

 black; hind coxal articular surface luteous, bell-shaped, but more produced 

 behind and not reaching the base of the coxa-. Wings luteous-brown, more 

 deeply so across the middle; stigma yellow; halteres yellow, the knobs slightly 

 brownish. 



The above description was made from a paratype 

 loaned by Dr. J. R. Malloch, labelled, "St. Joseph, 111., 

 May 10, 1914, Salt Fork." 



The outstanding differences distinguishing ontarioen- 

 sis from this species are: ontarioensis — middle coxal 

 process smaller; hind coxal spur larger, stouter; hind 

 trochanteral process half black, the end slightly com- 

 pressed; articular surface on outer side of hind coxae 

 much smaller, but broader at base; wings darker; 

 hypopygium not all black pilose; face more projecting 

 below; ventral tubercles smaller, and venter of third 

 segment not rugose. 



These species are of much interest, evidently rep- 

 resenting an evolutional stage. (See note in appendix.) 



Genus Pipiza Fallen (Fig. 43) 

 Face much broader at oral margin than at base of 



