The American Voles of the Genus Evotomys. 117 



gapperi Near Lake Simcoe, Ontario, Canada. 



ochraceus Mount Washington, New Hampshire. 



" rhoadsi Mays Landing, New Jersey. 



" loringi , Portland, North Dakota. 



' ' galei Ward, Colorado. 



" saluratus Nelson, British Columbia. 



brevicaudus Custer, Black Hills, South Dakota. 



carolinensis Roan Mountain, North Carolina. 



ungava Fort Chimo, Ungava. 



idahoensis Sawtooth Lake, Idaho. 



mazama . . Crater Lake, Oregon. 



obscurus Prospect, Oregon. 



calif ornicus Eureka, California. 



occidentalis Aberdeen, Washington. 



nivarius Mount Ellinor, Olympic Mountains, 



Washington. 

 proteus Hamilton Inlet, Labrador. 



KEY TO SPECIES AND SUBSPECIES OF EVOTOMYS. 



Ears distinctly rufous-tipped, not gray or dusky. 



Tail more than twice the length of hind foot. 

 Dorsal stripe not sharply defined. 



Ears small, scarcely protruding from fur, dorsal 



area ill defined, dull chestnut ungava. 



Ears large, prominent above fur, dorsal area dark 

 chestnut, blending with color of sides (winter 



pelage) carolinensis. 



Dorsal stripe sharply defined. 



Tail scarcely more than twice the length of hind 

 foot, about 27 per cent, of total length. 

 Dorsal stripe bright chestnut, with scattered 



black hairs, color sometimes dichromatic, .gapperi. 

 Dorsal stripe dull rusty rufous without black 



hairs, color not dichromatic ochraceus. 



Tail considerably more than twice the length of 

 hind foot, about 30 per cent, of total length. 

 Large, hind foot 20 or more ; colors dichro 

 matic, a red and a gray pelage proteus. 



Smaller, hind foot less than 20 ; not dichro 

 matic. 

 Skull with pronounced superciliary ridges 



in adults, size medium galei. 



Skull without pronounced superciliary 



ridges in adults, slightly larger saturatus. 



Tail less than twice the length of hind foot. 

 Dorsal stripe sharply defined, tail bicolor. 



Size large, foot 20 mm., dorsal stripe ferruginous. 



