INSKCUTOR INSCITI^ M^NSTRUUS 136 



Arista about equal to width of frons measured at base of 

 antennae; third antennal joint subquadrate, hlackish. . .lucta Snow. 

 Antennae reddish yellow to brown; tibiae and tarsi partly 



brown ; arista about one and half times width of frons 19 



19. Length of frons about twice its width; arista noticeably 



pubescent; hind metatarsus thickened (Virginia, Maryland, 



Pennsylvania, New Jersey, New York) similis Shannon. 



Length of frons nearly three times its width; arista very 

 faintly pubescent; hind metatarsus equal in girth to tibia 

 (Ontario) rita Curran. 



20. Legs and antennae entirely black (Colorado) lucta Snow. 



Legs and antennae partly yellowish 21 



21. Scutellum with a distinct groove-like depression near apical 



border ; arista much longer than width of frons ; third 



antennal joint enormous 22 



Scutellum with an evenly convex surface ; arista much shorter 

 than width of frons 24 



22. Legs almost entirely yellow (Pennsylvania) prima Hunter. 



Femora, except their apices, black 23 



23. Third antennal joint as broad as distance between root of 



antennae and eye margin, and with a distinct slit on inner 



surface (Virginia, Maryland, Pennsylvania) capillata Lw. 



Third joint much broader than this distance and without a slit 



(New Hampshire) slossoni, n. sp. 



24. Third antennal joint longer than broad, brownish (Indiana), 



caltha, n. sp. 

 Third joint circular 25 



25. Frons flattened; shining black species (Canada) comosa Lw. 



Frons not flattened, trisulcate 26 



26. Third joint reddish yellow; general color shining aeneous 



(Colorado) brevichaeta, n. sp. 



Third joint brown; general color shining black (Colorado), 



tarda Snow. 



indeterminate; species 



There are two described species which the author is uncer- 

 tain of regarding their position in the key, hence are given 

 here with what appears to be their sahent characters. 



Chilosia chintimini Lovett ( Proc. Cal. Acad. Sci. XI, 15, 

 1921). 

 Male. — Eyes pilose, face hairy ; no bristles anywhere. Nearly 

 black with mostly black pile. Similar to ferruginca and lasi- 



