1895. FBOCEEDIXGS OF THE NATIONAL MUSEUM. 411 



3. Abdomen, tibite, and knob of lialteres yellow, legs of female ciliate with 



nearly erect scales testacea. 



Abdomen, tibia', and knob of lialteres black pectoris (p. 420). 



4. Thorax marked with three black vittic (median and lateral) ; wings, abdomen 



and knob of lialteres blackish, legs of female not ciliate with scales.. 8 



Thorax marked with only one black vitta (median) 5 



Thorax marked with two black vittic, abdomen largely black, legs of female 



not ciliate with scales vittata. 



5. Thorax shining 6 



Thorax opa(xue, hypopyginm of male scarcely longer than the preceding 



segment; under side of middle and hind femora of female, and both 

 sides of middle and hind tibia>, ciliate with scales colorata (p. 420). 



6. Wings, abdomen and knob of halteres blackish, hypopyginm of male erect, 



nearly one-half as long as the abdomen 7 



Wings hyaline, abdomen yellow, hypopyginm small, porrect sellata. 



7. Hypopyginm of male bearing a tooth and notch on hind margin of lower 



lamella; both sides of all femora and tibi» of female, and upper side 



of all metatarsi, ciliate with scales fumosa. 



Hypopyginm destitute of a tooth and notch on the lower lamella, both sides 

 of all femora and tibia' of female, and upper side of only the hind 

 metatarsi, ciliate with scales lonijicaiida. 



8. Pleura and venter partly blackish ; length, 4 mm iixlchra. 



Pleura and venter wholly yellowish ; length, 6 mm glabra. 



9. Femora black or dark brown 49 



Femora largely or wholly yellowish 10 



10. Middle, or at least the hind coxtc, black or dark brown 11 



Middle and hind coxic yellowish 22 



11. Males 12 



Females 16 



12. Eyes contiguous or nearly so 13 



Eyes distinctly separated, abdomen wholly black or brown ; knob of halteres 



whitish ; length, 4 to 5 mm 15 



13. Central filament of hypopyginm free, very flexuous toward the apex 14 



Central filament free except at apex, not flexuous nor fractm-ed; middle 



lamelhe yellow, not jiroduced upward in a long conical process beyond 



apex of the black upper lamella' ; length, 8 mm rava (p. 410). 



Central filament hidden except on its lower one-third; abdomen depressed, 

 opaque ; middle lamella? of hypopyginm beyond apex of the upper one 

 not produced in a conical process; length, 8 mm ravida (j). 418). 



14. Abdomen wholly black, shining, central filament not fractured; length, 6 



mm j)uUa. 



Abdomen more or less yellow, compressed, shining, central filament fractured 

 toward the base, a brown cloud near forking of second and third veins, 

 hind femora thickened ; length, 5 mm rustica. 



15. Hind tibi;e Avith a large swelling near the base, central filament of hypo- 



pyginm with a U-shaped flexure near its base; inhabits California 



lonpedis (p. 419). 

 Hind tibia? destitute of swellings ; inhabits Illinois vmtahiUs. 



16. Abdomen opaque, knob of halteres yellowish 17 



Abdomen shining 18 



17. Length, 8| mm. ; antennal style about one-third as long as the third joint, 



wings brownish ravida (p. 418). 



Length, 5 mm. ; antennal style one-fifth as long as the third joint, wings 



hyaline mutahilis. 



