2 20 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



been found in practically every one of the other eight or 

 nine neighboring similar mountain streams which run down 

 from the Santa Cruz and Santa Morena mountains eastward 

 into the northern end of the Santa Clara Valley. And 

 across the valley, fifty miles away to the south and east, the 

 writer found two of these species in a stream (the Coyote) 

 running from the Coast Range westward into the valley. 

 Beyond, however, the mere facts of this contrasting local 

 distribution, nothing can be offered here; we have not 

 fairly begun to understand these strange and absorbingly 

 interesting flies. 



VI. Work to be Done. 



As this paper has been cast in its present form chiefly for 

 the sake of serving as a sort of introduction to the study of 

 the Blepharoceridse by American students, this end will 

 certainly only be furthered by calling specific attention to 

 the most apparent desiderata in the knowledge of this group. 



First, there are more species to be found in this country; 

 wherever there are mountains or hills with swift, clear 

 streams, it is safe to assert that Blepharoceridas will be 

 found there. Dipterologists have spoken to the writer of 

 the rarity of these flies ; but in an inspection of the region 

 within twenty miles of his laboratory, every stream of a 

 dozen was found to be invaded by the family, and in two 

 years of unsystematic search as many more species have 

 been added to the North American fauna as have been 

 recorded since the first Ble-pharocera ca-pitata was found in 

 1881. On a pleasure trip to Colorado, the four streams 

 near the camping ground were all found inhabited by 

 Blepharocerids ; and in a careless stroll along the banks of 

 the St. Lawrence, near Quebec, the characteristic larvse 

 were seen in the first brooklet peered into ! Let the streams 

 of the Ozarks, the Georgia hills, the Tennessee and North 

 Carolina mountains, the Cascades and Olympics of the 

 Puget Sound region, the Rockies of New Mexico and 

 Arizona, and the mountains of Southern California be 

 looked into. 



