Fes., 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 vellowish 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 11 inches. 
Tail about % or more of total length, black tip of tail long, its beginning not 
sharply defined; 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 defined; 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 4% 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 cirognanii, 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. 
