EMPIDIDJE. 73 



tarsi flattened, etc.; pulvilli present, the empodia usually 

 membranaceous and linear. Neuration variable ; the discal 

 cell sometimes absent, the third longitudinal vein furcate or 

 simple ; three or four posterior cells present ; anal cell often 

 shorter than the second basal cell, closed before the margin of 

 the wing*; sometimes wholly wanting. 



The family Empididee is a large one, including many genera 

 and species. Most flies belonging here will be at once recog- 

 nized, but there are some, especially those of the subfamily 

 Tachydrominae, which have such peculiar neuration that they 

 are apt to lead the student astray ; some may even be sought 

 for among the smaller Muscids. The flies are all predaceous, 

 though obtaining part of their food at times from flowers. 

 Many species, especially those of Empis and Rhamphomyia 

 often fly in swarms, dancing up and down over running brooks, 

 in the shade of trees or about shrubbery. Very rarely do any 

 species reach the length of ten millimeters, and some are not 

 more than three in length. 



The larvae are cylindrical, with small swellings on the under 

 side, from the mesothoracic segments, for locomotion. They 

 are probably carnivorous and live in the earth, under leaves 

 or other decaying vegetable matter. The pupae are free, with 

 two porrect points at the anterior end. 



TABLE OF GENERA. 



1. Anal cell closed in the border or narrowly open; body without macro- 



chsetae. . . . ' . . . . . . HILARIMORPHIN.E. 



Anal cell closed before the border when present. ... 2 



2. Anal cell wanting ; when present the front femora shorter or but little 



longer than their coxae. ... . . . TACHYDROMIN^. 



Anal cell present; front femora much longer than their coxas. . 3 



* Mythicomyia, a genus of doubtful relationship, has the anal cell open. 

 In Hilan'morpha it is closed in the margin. Both genera also differ from 

 other Empididae in being destitute of macrochastaa. Osten Sacken and 

 Schiner locate the latter genus among the Leptidae. If that view is ac- 

 cepted, Afi/thicomyia should probably accompany it. 



9 



