ADAMS : NORTH AMERICAN DIPTERA, 437 



21. Wings uniformly subfuscous , 22 



Wings darkest along the veins thoracica Say. 



22. Pile of cheeks black ( male ), and white ( female ) lucifera, n. ep. 



Pile of cheeks yellow or golden yellow 23 



23. Tibife brownish black (Mexico) mexicana Bell. 



Tibia? yellow flaviharhis, n. sp. 



24. All veins distinctly clouded with brown, 8-12 mm fceda Loew. 



A large subquadrate spot in center, and sometimes on base, of wing 



brown quadrata Say. 



Wings slightly infuscated at tip aincalis v. d. Wulp. 



Wings uniformly subfuscous 2^'>^opinqua Walk. 



Stigma and cross-veins only clouded 25 



25. Thorax brownish, with an obsolete, dorsal stripe of a darker shade, 



5-6 mm griffithi John. 



Mesonotum opaque brown, with lateral margins and three median nar- 

 row stripes lighter colored, 7 mm. (Mexico) laUfrons Will. 



26. Wholly yellow flavida Bigot. 



Not wholly yellow 27 



27. Wings wholly or in part fuscous 28 



Wings hyaline, apex grayish , 30 



28. Wings with central quadrate spot quadrata Say. 



Wings without such spot 29 



29. Wings uniformly infuscated ( Mexico ) plebeia Will. 



Wings fuscous on distal part (Mexico) nana Will. 



30. Wings broad and rounded rotundii^ennis Loew. 



Wings not broad and rounded (West Indies) ludens Loew. 



I hesitate in offering the above table, for I realize its defi- 

 ciencies. I have not seen all the species mentioned and had to 

 to depend on the descriptions ; therefore, it should be used as 

 a guide for the study of the genus rather than an implement for 

 the accurate placing of the species. 



Chrysopila lucifera, n. sp. 



Male : Head black ; frontal triangle, face and cheeks gray 

 poUinose ; antennse and palpi black, the latter long, subclavate, 

 thickly black pilose ; proboscis with brownish cast ; pile of 

 cheeks black. Thorax black, pollen dark gray on mesonotum, 

 light on pleurae ; mesonotum with golden yellow tomentum, 

 sparse pile dark brown ; scutellum black, golden yellow tomen- 

 tose ; halteres black. Abdomen black, tomentum of dorsum 

 golden yellow ; pile white. Coxae black, with black pile ; femora 

 blackish, tibiae and base of tarsi yellow. Wings subfuscous ; 

 stigma slightly elongate ; bend of anterior branch of third vein 

 rectangular, sometimes furnished with a stump. 



