Fes., 1912. Mammats or ILLInois AND WISCONSIN — Cory. 99 
habits, varying from the arboreal and semi-aerial little Flying Squirrel 
to the terrestrial and burrowing Woodchuck or “Groundhog.” In 
all the species the lower leg bones are separate and the skull shows 
well marked post-orbital processes. The tail is always more or less 
bushy (never bare or scaly). Generally there are two premolars on 
each side of the upper jaw, but the first is always small and often absent. 
The molars are tuberculate and rooted. Some species hibernate in 
this latitude and some do not. Squirrels’ hair is used in the manu- 
facture of the so-called ‘‘Camel’s hair’’ brushes. 
KEY TO THE GENERA 
IN ILLINOIS AND WISCONSIN. 
GROUP 1. Length of body, without tail, (nose to root of tail) more than 14 inches; 
tail less than 14 total length of body and tail. Genus MARMOTA, p. 150, 
GROUP 2. Length of body, without tail, less than 14 inches; tail 14, or more, total 
length of body and tail. 
SECTION 1. Back with several distinct stripes. 
Back with four pale stripes and several black ones; no rows of round pale 
spots. Genus EUTAMIAS, p. 135. 
Back with two pale stripes and several black ones; no rows of round pale 
spots. Genus TAMIAS, p. 128. 
Back with rows of pale, rounded spots down middle of each dark stripe. 
Genus CITELLUS, p. 137. 
SECTION 2. Back without several distinct stripes; front and hind legs not 
joined together by a thickly furred expansion of loose skin. 
Part 1. General color largely gray or grayish. 
Hairs distinctly vermiculated with black; tail vertebra always less than 
6% inches long. Genus CITELLUS, p. 137. 
Hairs not distinctly vermiculated with black; tail vertebrae more than 
614 inches long. Genus SCIURUS, p. 108. 
Part 2. General color largely red brown, tawny or yellowish. 
Genus SCIURUS, p. 108. 
SECTION 3. Back without distinct stripes; front and hind legs joined together 
by an expansion of loose skin extending laterally from side of body. 
Genus SCIUROPTERUS, p. 102. 
KEY TO THE SPECIES. 
GROUP 1. Length of body, without tail, (nose to root of tail) more than 14 inches 
long. 
General color grizzly brown; feet brownish black; about size of Domestic Cat 
or larger. Occurs in Illinois and Wisconsin. 
Woopcuuck, Grounp Hoc. Marmota monax, p. 150. 
Similar but smaller, and under parts more rusty brown. Occurs in extreme 
northern Wisconsin. CANADA WOODCHUCK. 
Marmota monax canadensis, p. 157- 
