VOL. XI, PP. 113-138 MAY 13, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



REVISION OF THE AMERICAN VOLES OF THE GENUS 



EVOTOMYS. 



BY VERNON BAILEY. 



The following brief synopsis of the Red-backed Voles is based 

 on a study of specimens in the collection of the U. S. Biological 

 Survey and the private collections of Dr. C. Hart Merriam and 

 Mr. G. S. Miller, Jr., supplemented by a series of the Arctic 

 Evotomys rutilus from Alaska in the U. S. National Museum, which 

 I have been permitted to examine through the courtesy of Mr. 

 F. W. True. I am indebted to .Mr. Outram Bangs for the privi 

 lege of including Evotomys proteus, an interesting new species 

 from Labrador, of which he has kindly sent me his manuscript 

 description and a series of specimens. In all, 650 specimens of 

 Evotomys from 116 localities have been examined, and while it is 

 still desirable to obtain material from many additional localities, 

 especially specimens in different pelages from the same place, 

 the present collections cover the ground fairly well. 



The genus Evotomys is circumpolar, inhabiting the northern 

 parts of Europe, Siberia, and North America. The only circum 

 polar species is the Arctic E. rutilus, which does not undergo any 

 considerable change throughout the circumference of the Arctic 

 Zone. None of the other species are common to both continents. 

 The North American forms are boreal in range, covering almost 

 the whole of Alaska, Canada, and the colder parts of the northern 

 United States, and extending southward in the mountains to 

 North Carolina and Colorado, and along the sea coasts to New 

 Jersey and northern California. Excepting the southern Sierra 

 Nevada in California and a few isolated mountains in various 



27-BioL. Soc. WASH., VOL. XI, 1897 (113) 



