64 Illinois State Laboratory of Natural History. 



G. Cyclops viridis Jurine. 



Either the typical form or its varieties occur everywhere 

 in the fresh waters of the United States. It is the commonest 

 form of the temporary ponds. 



a. var. brevispinosus Herrick. 



b. var. insectus Forbes. 



7. Cyclops bicuspidatus Glaus. 



This species is of the widest range and greatest abundance. 

 It is the commonest Cyclops in the Great Lakes. 



8. Cyclops vernalis Fischer. 



Occurs in small numbers in Lake Geneva, Wisconsin. 



II. Subgenus Macrocy clops Clans. 



9. Cyclops fuscus Jurine. 



Occurs sparingly in the ponds and lakes of Wisconsin, 

 Michigan, Illinois, and Massachusetts. 



10. Cyclops albidus Jurine. 



Rather a common species throughout the whole range of 

 the genus. 



III. Subgenus Homocyclops n. subgen. 



11. Cyclops ater Herrick. 



Very rare throughout the Mississippi Valley. Also in Lake 

 St. Clair (Kofoid). 



IV. Subgenus Orthocyclops n. subgen. 



12. Cyclops mod est us Herrick. 



An uncommon species in the lakes and streams of Wyo- 

 ming, Alabama, and the north central States. 



V. Subgenus Microcyclops Claus. 



13. Cyclops bicolor Sars. 



Rare in Wyoming, Illinois, Wisconsin, Michigan, and Min- 

 nesota. 



14. Cyclops varicans Sars. 



A fairly common species throughout the range of Cyclops 

 in North America. 



