BOMBYLIIM). 



211 



Fig. 85. Exoprosopa y sp., en- 

 larged one half. After Kellogg. 



sometimes rudimentary, the empodia almost always so; 

 tarsi and claws usually small. Squamae small. Wings 

 often with dark markings; two or more submarginal,* 

 three or four, rarely fivet posterior cells present; discal 

 cell present in all our genera (absent in Apolysa, Cyrtosia}; 

 anal cell closed in or near the margin, or narrowly open. 



The family Bombyliidse 

 comprises about fifteen hun- 

 dred known species. Most 

 of them are swift-flying in- 

 sects, often hovering motion- 

 less in the air for a time and 

 darting away like a flash. 

 They seek sunny places in 

 woodland roads, about blos- 

 soms or on rank vegetation. 

 The Anthracinse are a group especially characteristic of 

 arid regions. In general the members of the family are 

 prettily and delicately marked, and their life histories 

 are often very interesting. In the adult state they are 



* The aberrant genus Mythicomyia described as an empidid, may 

 possibly belong in this family. Without expressing an opinion as to 

 its real relationships, it will be. easily recognized by its very short 

 second longitudinal vein, and its single submarginal cell. See figs. 

 25 and 26, and fig. 12 of the Bmpididae. 



t The presence of but four posterior cells in most members of this 

 family, as doubtless in other forms having a like number, is due to 

 the loss of the vein between the third and fourth cells, and not to the 

 coalescence of veins. Certain .species of Anthrax, and perhaps of 

 other genera, have this vein persistent or vestigial. In those species 

 having but three posterior cells the reduced number is likewise due to 

 the loss of the vein between the second and third cells, so that the 

 second posterior cell in such forms is really the coalesced second, third 

 and fourth posterior cells (see figs. 1 and 21). This does not accord 

 with the Comstock-Needham system of nomenclature, but I believe is 

 certainly demonstrable. 



