THE CHICAGO ACADEMY OF SCIENCES. 



The above total reveals certain interesting facts. The Canadian 

 region is the best represented, containing 50 species and varieties, or 

 nearly one-half of the total fauna. The Upper Mississippian region 

 is next in representation, 36 species and varieties being known. The 

 Columbian (22), the Nova Scotian (24), the Californian (19) and 

 the Hudsonian (16) regions also contain a high percentage of species. 

 The poorly populated areas are the Carolinian (4), Central American 

 (3), West Indian (3), Greenlandian (3) and the Labradorian (1) 

 regions. Only three species are common to America and Asia. 



The country surrounding the Great Lakes is at present the center 

 of distribution of this family, 55 species and varieties living in this 

 area, or more than half of the known species. Several species are 



