134 INSECUTOR INSCITI^ MKNSTRUUS 



5. Legs largely yellow ; face usually more or less yellow 6 



Legs largely black ; face black 7 



6. Scutellum partly yellowish; mesonotum brassy black (Cal- 



ifornia) townsendia Hunter. 



Thorax entirely steel blue (northeastern America), 



plumata Lw. ; cyanescens Lw. 



7. Shining blue species ; third antennal joint bright reddish yel- 



low (Oregon: nigro-coerula Lovett ; Washington), 



cyanea Hunter. 

 Shining black species 8 



8. Pile on dorsum of thorax black; tubercle prominent; third 



antennal joint reddish yellow (Alaska) gracilis Hunter. 



Pile on mesonotum at least partly luteous or whitish 9 



9. A tuft of black bristle-like hairs on the pteropleura, as well 



as mesonotum (Alaska) plutonia Hunter. 



Only light-colored pile on pteropleura 10 



10. Arista shorter than width of f rons at antennae ; legs solid 



black ; length 65 mm. (Nevada) plumosa Coq. 



Arista as long or longer than width of f rons 11 



11. Frons with luteous pile ; length 6.5 mm idahoa, n. sp. 



Frons with black pile; length 8 mm. (California) . .wiWuiom" Snow. 



12. Scutellum with bristle-like hairs, usually black 13 



Scutellum at most with a few long pale hairs 20 



13. Face, humeri and scutellum more or less yellowish 14 



Face and thorax black 16 



14. Arista very finely pilose; dorsum of thorax punctulate; pos- 



terior femora light-colored at apex only; black, moderately 



shining species (Carolina) lencoparea Lw. 



Arista noticeably pubescent ; greenish black species 15 



15. Legs almost entirely yellow, yellow markings of face and 



thorax bright lemon yellow (District of Columbia) . . .palUpes Lw. 

 Legs with more or less black ; yellow markings of more or 

 less obscured color (northern North America : tristis com- 

 plex tristis Lw. 



16. Third antennal joint very large, six times or more than that 



of the second, and bright orange (Alaska) kincaidi, n. sp. 



Third joint not half so large 17 



17. Tarsal joints dilated, particularly the posterior ones; pile 



everywhere pale, even the scutellar bristles (Arizona, Mex- 

 ico) sororocula Will. 



Tarsi not dilated, bristles black 18 



18. Entirely shining black (Washington) laezns Bigot; (Colo- 



rado) lucta (?) Snow. Other characters for Iiicfa are: - 



