248 



ila than to Mycetobia, as is evidenced by the complete media, and 

 by the presence of the subcostal cross-vein in P. johnsom. Ditomyia 

 and Symmerus both lack the basal part of media and the subcostal 

 cross-vein, while, in addition, the subcostal vein is incomplete. 

 Mycetobia belongs to Rhyphidae. 



There are two North American species of Palacoplatyura, and 

 four of Bolitophila, — two of which, cinerea and hybrida, occur also in 

 Europe. 



Key to Genera 



1. Medio-eubital cross-vein proximad of radio-medial, so that the 2 

 cells separated by basal portion of media are very unequal in 

 length Bolitophila. 



— Medio-cubital cross-vein almost in vertical line with radio-medial, 



so that the 2 cells separated by basal portion of media are almost 

 equal in length Palaeoplatyura. 



Key to Imagines of Bolitophila Meigen 



1. Fork of third vein ends in first branch of radius (Europe; N. Y.) 



cinerea Meigen*. 



— Fork of third vein ends in costa 2 



2. Anterior branch of cubitus discontinued some distance from base 



(Idaho ; N. H.) disjuncta Loew. 



— Anterior branch of cubitus complete 3 



3. Subcostal vein ends in costa at a point above or beyond the base of 



radial sector — third vein (N. H. ; Ind. ; B. C.) . .hybrida Meigen. 



— Subcostal vein ends in costa at a point much proximad of base of 



radial sector (N. H. ; N. Y.) montana Coquillett. 



Key to Imagines of Palaeoplatyura Meunier 



1. Wings unmarked; subcostal cross- vein absent ("Wash.) 



aldrichi Jnhannsen. 



— Wings with grayish or fuscous markings ; subcostal cross-vein pres- 



ent (Vt.) johnsoni Johannsen. 



*The larva of Bolitophila cinerea has been figured and briefly described by Dr. 

 Felt in the Twenty-ninth Eeport of the New York State Entomologist, p. 67. (1915) 



Family MYCBTOPHILIDAB 



The limits of this family are somewhat doubtful, and the most 

 recent papers on it seem to me to include a rather heterogeneous as- 

 semblage of genera that require considerable family subdivision. The 



