106 THE CANADIAN ENTOMOLOGIST 



21. Prealar bristle present but small; hind femur bare at middle on posteroveii- 



tral surface; mid tibia without anterodorsal or posteroventral bristles; 



fifth sternite without strono^ bristles dupUcafa Meigen 



— Prealar bristle absent or minute ; hind femur with one or two strong, but 

 not very long bristles at middle of posteroventral surface; mid tibia 

 with one or two anterodorsal and posteroventral bristles; fifth abdom- 

 inal sternite with a very strong bristle on each side of 

 cleft bispinosa Malloch 



22. Thorax shining fulvous, without conspicuous i)ruinescence ; facets on upper 



half of eyes very conspicuously enlarged, the head flattened above ; 

 arista plumose Hebccnciua fulva ( Bigot) 



— Thorax if fulvous with distinct pruinescence; facets of eyes but little en- 



larged above, the head not flattened; arista very short haired 23. 



23. Hind tibia with two or more anterodorsal bristles; hind femur with eighi 



to ten bristles extending from middle to apex on anteroventral surface, 



the longest bristles distinctly longer than the diameter of 



femur lysinoc Walker 



— Hind tibia with one anterodorsal bristle; hind femur with three or four 



short bristles at apex on anteroventral surface, none of which exceed 

 in length the diameter of femur uniscia v^tein. 



24. Scutellum with a conspicuous black spot on each side at 



base iiligiiiosa Fallen 



— Scutellum without such spots 25. 



25. Abdomen with an indistinct black dorsocentral vitta ; mid tibia with one or 



two anterodorsal bristles; fore tibia with two posterior bristles; basal 

 abdominal sternite setulose linearis Malloch 



— Abdomen with paired spots on dorsum which are sometimes indistinct ; 



mid tibia almost invariably without anterodorsal bristles 26. 



26. Eyes separated by one third of the head-width; only the fore femora black- 



ened; spots on dorsum of abdomen very 



indistinct splnilamellata Malloch 



— Eyes separated by much less than one third of the head-width, or not other- 



wise as above 27. 



27. Posteroventral surface of hind fenuir with long hairlike bristles on almost 



its entire length or on basal half; j)osterodorsal surface of hind tibia 

 with from one to three short setulae 28. 



— Posteroventral surface of hind femur bare or with a few bristles at middle 



or near apex; posterodorsal surface of hind til)ia without setulae ex- 

 cept in abicns and spuria 30. 



28. Hind tibia with long soft hairs on ventral surfaces. . . .consimilata Malloch 



— Hind tibia with a few small bristles on anteroventral and posteroventral 



surfaces, the ventral surface bare 29. 



29. Eyes separated by three times the width across posterior ocelli ; legs 



black flctcheri Malloch 



— Eyes separated by less than twice the width across posterior ocelli ; tibiae 



and apices of femora reddish yellow nigribasis Malloch. 



