184 Field Museum of Natural History — Zoology, Vol. XL 



GROUP 2. Species which occur in southern Illinois. 



SECTION 1. General color of upper parts brown but not golden brown. 



Total length usually more than 7 inches; tail vertebrae more than 3 inches. 



Western Cotton Mouse. 



Peromyscus gossypinus megacephalus , p. 196. 



Total length less than 7 inches (usually about 6.75 in.); tail vertebrae not 



exceeding 3 inches (usually 2.75 to 3 in.). White-footed Mouse. 



Peromyscus leucopus, p. 184. 

 Total length 5.50 to 6.50 inches; tail vertebrae less than 2.75 inches. 



Prairie White-footed Mouse. 

 Peromyscus maniculatus bairdi, p. 190. 



SECTION 2. General color of upper parts golden brown. Upper parts, includ- 

 ing head, rich golden brown. Southern Golden Mouse. 



Peromyscus nuttalli aureolus, p. 198. 



GROUP 3. Species which occur in northern Wisconsin. 

 Tail vertebrae usually from 3.25 to 4 inches long. 



Canadian White-footed Mouse. 

 Peromyscus maniculatus gracilis, p. 193. 



Subgenus PEROMYSCUS Gloger. 



Plantar tubercles 6; ears dark or dark v^^ith whitish edges; dentine 

 spaces of molars mostly confluent. 



Peromyscus leucopus (Rafinesque). 



White-footed Mouse. Deer Mouse. White-footed Wood 



Mouse. 



Musculus leucopus Rafinesque, Amer. Monthly Mag., III., 1818, p. 446. 



Peromyscus leucoptis Rhoads, Proc. Acad. Nat. Sci. Phila., 1896 (1897), p. 187 

 (Tennessee). Hahn, Ann. Rept. Dept. Geol. & Nat. Resources Ind., 1908 (1909), 

 p. 496 (Indiana). Osgood, N. Amer. Fauna, No. 28, 1909, p. 113 (Kentucky, 

 Tennessee, etc.). 



Type locality — Western Kentucky. 



Distribution — From the Atlantic coast of Virginia and North Carolina 

 westward around the southern end of the Allegheny Mountains, 

 through northern South Carolina and Georgia to Oklahoma, north 

 to southern Illinois and south to southern Louisiana. 



Description — Adult: Upper parts brown, darker on middle of back 

 than on sides; under parts white, the concealed bases of the hairs 

 slaty gray, the tips white; upper surface of tail brown, under surface 

 whitish. 



Young: Feet white; plumbeous gray all over except the belly 

 where the hairs are tipped with white. 



