THE NORTH AMERICAN TWO-WINGED FLIES OF THE 

 FAMILY SIMULIIDAE 



By Harrison G. Dyar, 



Custodian of Lepidoptent, Uivited States Nalional Miisoan, 



and 



Ivay:>[oni) C, Shanxox, 



Of the Bureau of Entomology, United States Department of AgricnJiure 



Since the publication of J. R. Malloch's treatment of the "Ameri- 

 can Bhick Flies or Buffalo Gnats '' in 1914 \ the collection of these 

 insects in the ITnitod States National Museum has been increased 

 several fold. The present publication is based on the material used 

 bv jNIalloch. and the additional material which has been collected 

 mostly by Dr. J. M. Aldrich and the writers. Also material has 

 been loaned us by J. S. Hine. the Illinois Natural History Labora- 

 tory (through T. H. Frison). the Biolooical Survey, and H. C. 

 Hallock. 



The freneric arrangement here used is primarily based on a previ- 

 ously unused character, namely, the presence or absence of hairs on 

 the second section of the radius (between the stem vein and base of 

 the radial sector). Only 4 genera are here recognized, which is in 

 sharp contrast to the IT recognized by Enderlein. We have found 

 Enderlein's classification entirely unsuited to the American fauna. 

 Both Eusimulkmi 'peeuaruni and vintatum which he places in the 

 subfamily Prosimuliinae, a group based on the character of the 

 forking of the radial sector, have the radial sector simple. In fact, 

 he erected the genus Cne'pha to contain these two species upon this 

 particular character which, we have just mentioned, they lack. In 

 practically all other instances where the American fauna is involved 

 in his treatment we have found that the genera he proposed are too 

 finely drawn and of no practical value. 



The region included in the present work is the mainland of North 

 America and Greenland. Forty-seven species and two races are 

 recognized, of which we have more than 3,000 adult specimens. Mal- 



lU. S. Dept. Agr., Bur. Ent. Tech. Scr., No. 26, 1D14. 



No. 2636.— Proceedings U. S. National Museum. Vol. 69. Art. 10. 

 .tin:;— 27 1 1 



