North American Fresh-water Cyclopidce. 63 



rulatas. This lake is in the Cascade Mountains and is the 

 highest lake of its size in the world. 



As very few observations have been made on the Cyelopidse 

 of rivers, I examined a continuous series of collections made 

 in the Illinois Eiver at the Illinois Biological Station, ex- 

 tending from May to September, 1896. In the first of these 

 collections bicuspidatus was the predominating form, but it 

 soon disappeared entirely, its place being taken by viridis 

 var. insectus. From this time throughout the summer insectus 

 was by far the most abundant form. Edax, viridis var. 

 brevispinosus, leuckarti, prasinus, semdatus, and vari cans were 

 common in the collections, while Jimbriatus var. poppei, viridis, 

 modestus, bicolor, albidus, and phaleratus were of rare occur- 

 rence. 



LIST OF NORTH AMERICAN SPECIES. 



Below is a list of the fresh-water Cyclopidre reported from 

 America. I have myself seen all of the species of this list 

 except those herein credited to Herrick. 



Genus CYCLOPS. 



I. Subgenus Cyclops s. str. Claus. 



1. Cyclops leuckarti Claus. 



This is a rare species throughout the north central States. 



2. Cyclops insignis Claus, fide Herrick. 



Herrick has found at Long Island a form which he identi- 

 fies as this species. 



3. Cyclops edax Forbes. 



This is a very common species in the Great Lakes and in 

 the waters of the north central States, Florida, and Wyoming. 

 It occurs in Argentina, South America. 



4. Cyclops oithonoides Sars^/zWt' Herrick. 



I regard the occurrence of this species in America as very 

 doubtful. 



5. Cyclops dybowskii Lande. 



A rare species found only in the small mountain lakes of 

 Wyoming and in a temporary pond at Urbana, Illinois. 



