104 THE CANADIAN ENTOMOLOGIST 



bare ( Cicn. n. ) iiianiiorata Meigen ? 



— Hypopleura bare; if with a few hairs below spiracle the sides and ventral 



surface of scutellum are bare ; first abdominal sternite sometimes with, 

 a few hairs 4 



2. Hind femur with a few bristly hairs at apex on posteroventral surface, none 



of which are nearly as long as the diameter of femur where they are 

 situated; eyes densely long haired, separated by a little more than width 

 of anterior ocellus iiiitltiscfosa vSchnabl 



— Hind fenuir with a number of bristles at apex on posteroventral surface, 



most of which are distinctly longer than diameter of femur where they 

 are situated -">• 



3. Eyes densely long haired, separated by a little more than width of anterior 



ocellus; black species, more or less densely gray pruinescent, but the 



dorsum of thorax always shining Incorum Fallen 



Eves rather sparsely haired, separated by distinctly more than the width 



across posterior ocelli; black species, the entire body densely gray pruin- 

 escent, the dorsum of thorax not distinctly shining punctata Stein 



4. Legs entirely black 5 



— Legs partly yellowish or reddish 13 



5. Eyes separated by nearly one third of the head-width ; mid tibia with two 



very strong anterodorsal bristles; hind tibia with one or two bristles 

 near base on posterodorsal surface; first abdominal sternite 

 setulose latifrontata Malloch 



— Eyes separated by much less than one third of the head-width ; mid tibia 



withcmt anterodorsal bristles except in iiilida and nigrita 6. 



6. Knobs of halteres black 7. 



— Knobs of halteres pale 9. 



7. Margins of calyptrae black; eyes with short hairs; arista with its longest 



hairs as long as width of third antennal segment; posteroventral sur- 

 face of hind femur without strong bristles; basal abdominal sternite 



setulose nitida v^tein 



 — Calyptrae yellowish, margins pale : eyes bare  8. 



8. Posteroventral surface of hind femur with a series of strong bristles ; long- 



est hairs on arista not longer than its basal diameter; basal abdominal 



sternite bare ; prealar bristle moderately long hanna'i sp. n 



Posteroventral surface of hind femur almost bare; longest hairs on arista 

 longer than width of third antennal segment ; ])realar bristle absent or 

 minute; basal abdominal sternite bare. . . .Hebccnema vespcrtina Fallen 



9. Mid tibia with a small protuberance on posterior side beyond middle, which 



is covered with short setulae, and basad of the protuberance about ten 

 * long bristles on the same surface tiihcrciilata Malloch 



— Mid tibia without such protuberance and bristles 9a. 



9a. Hind femur with a series of long bristles from base to apex on antero\en- 

 tral surface, the length of the bristles exceeding the diameter of femur; 

 a few weak hairs sometimes below metathoracic spiracle; basal abdom- 

 inal sternite setulose nasoni Malloch 



