THE CANADIAN ENTOMOLOGIST. 115 



Mesonotum not strongly punctured, and with distinct 



stripes 12 



12. Head produced anteriorly; third joint of antenna at least 1 ] 4 



times as long at base *Parectecephala Becker. 



Head not distinctly produced; third joint of antenna but little 

 longer than broad; dull yellow and black, robust species, 

 with black palpi *Anthracophaga Loew. 



13. Hind tibia with a distinct, curved, apical thorn on the anterior 



side 14 



Hind tibia without such thorn 17 



14. Frons with distinct orbital setulae 15 



Orbits with, at most, weak hairs 16 



15. Scutellum elongated, disk flattened; male proboscis with two 



long apical hairs Prohippelates Malloch . 



Scutellum not elongated, convex; male proboscis 



normal Pseudohippelates Malloch. 



16. Arista flattened, strap4ike Ceratobarys Coquillett. 



Arista not flattened Hippelates Loew . 



17. Second vein exceptionally short, third costal division much 



longer than second Siphunculina Rondani . 



Second vein not shortened, third costal as long as, or shorter, 

 than second 18 



18. Arista either broadened and strapdike, or with distinct pubes- 



cence 19 



Arista neither thickened nor distinctly pubescent 22 



19. Arista more or less distinctly flattened, the pubescence very 



close, giving the arista a knifedike appearance even when the 



arista itself is but slightly flattened 20 



Arista normal in shape, pubescence rather loose 21 



20. Scutellum subtriangular, the marginal bristles situated on 



small warts Crassista von Roser. 



Scutellum rounded in outline, the margin without 



warts Melanochceta Becker. 



21. Scutellum elongated, the disk flattened Gaurax Loew 



*The line of demarcation between these genera is very unsatisfactory, and 

 though I am rather inclined to reject PareCrtecephgla as entitled to geneiic rank, 

 I have not sufficient material before me to enable me to decide tin- matter 

 satisfactorily. 



