MOUNTAIN ANTS OF NORTH AMERICA. 



483 



As would be expected, the affinities between the Pacific Coast and 

 Eastern faunas are least developed, while those between the Sierra- 

 Cascade and Rocky Mts. and especially those between the latter and 

 the Eastern fauna are much greater. 



If to the Transition and Boreal forms included in the tables we add 

 the species, subspecies and varieties of the Lower and Upper Sonoran 

 and Lower and Upper Austral Zones, the quantitative and qualitative 

 differences between the western and eastern ant-faunas are even more 

 striking. The same would be true of a comparison of the subgenera 

 and genera of the two regions, for we find that, if we exclude the 

 neotropical elements, no less than eight genera and subgenera are 

 restricted to the western fauna {Liometopum, Messor, Deromyrma, 



