FEes., 1912. Mammats oF ILLINOIS AND WISCONSIN — Cory. 103 
Pteromys volucella AUDUBON & BACHMAN, Quadrupeds N. Amer., I, 1846, p. 216, 
/Laruam, Trans.’ Wis. State Agr. Soc, II, 1852 (1853), p. 339 (Wisconsin). 
KeEnnicort, Agr. Rept. for 1856, U. S. Patent Office Rept., 1857, p. 69 (Illinois). 
Ib., Trans. Ill. State Agr. Soc., I, 1853-54 (1855), p. 579 (Cook Co., Illinois). 
ALLEN, Proc. Bost. Soc. Nat. Hist., XIII, 1869 (1871), p. 189 (Iowa). STRONG, 
Geol. Wis., Surv. 1873-79, I, 1883; p. 439 (Wisconsin). 
Type locality — Virginia. 
Distribution — Southern New England to northern Georgia westward 
(except in the mountains); south of the Great Lakes and north of 
Alabama to Minnesota, Iowa and eastern Kansas; replaced in the 
South by a slightly different race — (S. v. querceti). 
Special characters — Hair on under parts entirely white to the base; 
fur very soft. 
Description — In summer: Upper parts grayish brown, more or less 
washed with russet brown, usually deepest on upper surface of 
tail; greater portion of upper surface of flying membrane dark drab 
brown; under surface of tail tawny or tawny white; rest of under 
parts white; the hairs entirely white to the bases. 
In winter: Similar, but the upper parts tinged with grayish 
brown. 
Measurements — Total length, 9.25 in. (234.5 mm.); tail vertebra, 3.90 
in. (99.7 mm.); hind foot, 1.22 in. (31.2 mm.). 
This graceful little animal is common in wooded districts through- 
out Illinois and the greater part of Wisconsin, but it is seldom seen on 
account of its nocturnal habits. During the day it sleeps in some 
hollow tree; but very late in the afternoon it occasionally, though rarely, 
may be seen sailing through the air on a downward slant, usually from 
the top of some tree to the trunk or lower branches of another, often 
at a considerable distance. 
The nest is in a hollow tree and is composed of leaves and moss. 
In the majority of cases a hole formerly occupied by a woodpecker is 
used. The young are from 4 to 6 in number and are generally born in 
April in this latitude. The young Squirrels make charming pets, 
being very gentle and affectionate. 
In a letter to Audubon and Bachman, which is quoted by them, Mr. 
Gideon B. Smith of Baltimore writes (J. c., p. 220): ‘They are gre- 
garious, living together in considerable communities, and do not object 
to the company of other and even quite different animals. For ex- 
ample, I once assisted in taking down an old martin-box, which had 
been for a great number of years on the top of a venerable locust tree 
near my house, and which had some eight or ten apartments. As the 
box fell to the ground we were surprised to see great numbers of Fly- 
