FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 359 



KEY TO OUR SPECIES. 



GROUP 1. Color brown all over, except usually a white spot on chin and sometimes 

 another on breast; belly not white or yellowish white; animal does not turn 

 white in winter. 



Belly brown; tail bushy, darker than the back and blackish at the end; total 

 length of males more than 19 inches; females smaller. 



MINK. Putorius vison lutreocephalus, p. 361. 



GROUP 2. Color (in summer) brown above, most of under parts (including belly) 

 white, yellowish white or yellowish buff; animal turns white in winter in this 

 latitude. 



SECTION 1. Total length of males usually more than 13 inches and of females 



usually more than 1 1 inches. 



Tail about > or more of total length, black tip of tail long, its beginning not 

 sharply denned; toes and feet generally without white; usually a brown 

 spot back of the angle of the mouth; under parts white, often more or 

 less tinged with lemon yellow. (In winter)* White all over (except 

 black end of tail), more or less tinged with lemon yellow, most pro- 

 nounced about rump, hind legs and tail. 



NEW YORK WEASEL. Putorius noveboracensis, p. 366. 



Black tip of tail short and abruptly denned; toes and feet with more or less 

 white ; under parts washed with ochraceous buff or deep saffron yellow. 

 (In winter) White all over (except black tip of tail), without yellow 

 tinge except at times on tail. MINNESOTA LONG-TAILED WEASEL. 



Putorius longicauda spadix, p. 374. 



SECTION 2. Total length of males less than 13 inches and of females less than 



ii inches. 



Male usually more than 8.50 inches long and female more than 7.50 inches 

 long; tail generally nearer }/ than % of the total length. (In summer) 

 Toes and generally inner sides, of hind feet usually with tinge of yellow. 

 (In winter) White all over, more or less washed with pale yellow most 

 pronounced on rump, hind feet and tail; end of tail always black. 



BONAPARTE'S WEASEL. Putorius ci^ognanii, p. 375. 



Males less than 8.25 inches long; females less than 7.50 inches. (In summer) 

 Brown above; under parts white or whitish; end of tail without black tip. 

 (In winter) Pelage entirely white; tail without black tip except occasionally 

 with a few blackish hairs at extreme end. 



ALLEGHENIAN LEAST WEASEL. 

 Putorius rixosus allegheniensis, p. 378. 



* Refers to specimens from Wisconsin and northern Illinois. In the southern : 

 part of its range it does not turn white in winter. . 



