ENTOMOSTRACA AND LIFE ZONES. QI 



the modification of Schimper's zones adopted by Ramaley in his 

 studies of the vegetation of the area. It seems desirable, how- 

 ever, to tie this fauna to the larger life zones which apply 

 throughout the continent as a whole and which have been mapped 

 out by Merriam and are now made use of by a considerable num- 

 ber of those interested in problems of distribution. Figure I 

 shows how these zones are distributed over the continent. Of 

 special interest are the southward extensions and islands of the 

 northern zones over the higher areas, as in the Appalachians, 

 Rockies, and Sierras. The outline of Colorado, indicated by the 



Arct/c-Alp/ne Hudsonian Canadian Transition Upper Sonoran 



FIG. 2. Life-zone map of the portion of Colorado where most of the writer's 

 collections were made. Shows close approach up Upper Sonoran and Arctic- 

 Alpine Zones and narrowness of other zones in this region. After Gary. 



black rectangle, shows the position of the area under considera- 

 tion with reference to one of these southward extensions. Gary 

 ('n) publishes a more detailed life-zone map of the state, a 

 small portion of which is reproduced in Fig. 2. This includes the 

 area from which most of my records come and shows that within 

 a few miles are met Upper Sonoran, Transition, Canadian, Hud- 

 sonian, and Arctic-Alpine Zones. 



