[K'eprinted from Journal of the New York Entomolocicai. Society, \"o1 

 XX., No. 2, June, 1912.] 



THE BIOLOGY OF SOME WESTERN SPECIES OF 

 THE DIPTEROUS GENUS EPHYDRA.^ 



By J. M. Aldrich, 

 Moscow, Ida. 



(With Plates VII to IX.) 



The investigation partially covered by this paper was first sug- 

 gested by a casual visit to the shores of Great Salt Lake in the summer 

 of 1908. The large number of new observations made in a couple of 

 hours at that time indicated the existence of a rich and almost unex- 

 plored field. Through the liberality of the trustees of the Elizabeth 

 Thompson Science Fund, I was enabled in the summer of 191 1 to 

 visit the principal salt and alkaline lakes of the Great Basin and 

 adjacent territory west and southwest. The present paper combines 

 the facts gathered in both years and those previously published, per- 

 taining to the biology of the genus Ephydra in the west. 



The bodies of salt and alkaline water visited by me in 191 1, with 

 dates of visits, are as follows : 



Box Elder Lake, Utah .• • • • July 4 and s 



Great Salt Lake, Utah — 



at Garfield (south end) July 9 



at Saltair (south end) July 10 



at Promontory Point (middle) July 1 1 



at Lakeside (west side) July 12 



Soda Lakes near Hazen, Nevada July 13 and 14 



^ Being a portion of the results of an investigation carried on with the 

 aid of an appropriation from the Elizabeth Thompson Science Fund. 



77 



