Fes., 1912. MAMMALS OF ILLINOIS AND WISCONSIN — Cory. 109 
KEY TO OUR SPECIES. 
A. General color largely gray or gray mixed with rusty; under parts white or whitish; 
hatrs on tail broadly tipped with white. 
Gray of upper parts more or less mixed with rusty. Occurs in about southern 
two-thirds of Illinois. SOUTHERN GRAY SQUIRREL. 
Sciurus carolinensis, p. 115. 
Similar but slightly larger and upper parts clear gray in winter. Occurs in 
Wisconsin and northern Illinois. NoRTHERN GRAY SQUIRREL. 
Sciurus carolinensis leucotis, p. 116. 
B. General color largely tawny gray; under parts not white (usually tawny); hairs 
on tail broadly tipped with tawny or pale rufous. 
WESTERN FOX SQUIRREL. Sciurus niger rufiventer, p. 109. 
C. General color reddish brown; under parts white; entire length, including tail, 
12 to 14 inches. RED SQUIRREL. Sciurus hudsonicus loquax, p. 122. 
D. General color black or partly black; color phases of: 
NORTHERN GRAY SQUIRREL. Sciurus carolinensis leucotis, p. 116. 
or WESTERN Fox SQUIRREL. Sciurus niger rufiventer, p. 109. 
Subgenus PARASCIURUS Trouessart. 
I-1 ; 
Premolars oe rostrum long and broad; brain case narrow at 
occiput; nasals relatively broad; molars large. 
Sciurus niger rufiventer (GEOFFROY). 
WESTERN Fox SQUIRREL. 
Sciurus rufiventer GEOFFROY, Cat. Mamm. Mus. d’Hist. Nat., 1803, p. 176. 
Sciurus occidentalis Aup. & Bacu., Proc. Acad. Nat. Sci. Phila., 1841, p. 102. 
Sciurus vulpinus Lapuam, Trans. Wis. State Agr. Soc., II, 1852 (1853), p. 339 
(Wisconsin). 
Sciurus magnicaudatus KENNIcoTT, Trans. Ill. State Agr. Soc., I, 1853-54 (1855), 
p. 579 (Cook Co., Illinois). Jb., Agr. Rept. for 1856, U. S. Patent Office Rept., 
1857, Dp. 55- 
Sciurus Sayi STRONG, Geol. Wis., Surv. 1873-79, I, 1883, p. 439 (Wisconsin). 
Sciurus ludovicianus Custis, Barton’s Med. & Phys. Journ., II, 1806, p. 47. ALLEN, 
Proc. Bost. Soc. Nat. Hist., XIII, 1869 (1871), p. 188 (Iowa). Muves, Rept. 
Geol. Surv. Mich. I, 1860 (1861), p. 220 (Michigan). Van Hynine & 
PELLETT, Proc. Iowa Acad. Sci., XVII, 1910, p. 214 (Iowa). 
Sciurus niger GARMAN, Bull. Essex Inst., XXVI, 1894, p. 6 (Kentucky). HERRICK, 
Geol. & Nat. Hist. Surv. Minn., Bull. No. 7, 1892, p. 158 (Minnesota). 
Sciurus niger rufiventer OsGoon, Proc. Biol. Soc. Wash., XX, 1907, p. 44. JACKSON, 
Proc. Biol. Soc. Wash., XX, 1907, p. 71 (Wisconsin). Hann, Ann. Rept. 
Dept. Geol. & Nat. Resources Ind., 1908 (1909), p. 466 (Indiana). 
