Fes., 1912. MaAmMALs OF ILLINOIS AND WISCONSIN — Cory. 261 
KEY TO THE GENERA. 
A. Interparietal not distinct in adult; postorbital process usually nearly or quite 
divergent from skull; hind foot, 5-or more inches long; our species turn 
white in winter. Genus LEPUS, p. 261. 
B. Interparietal distinct in adult; postorbital process more or less attached to the 
skull; hind foot, about 4 inches long in our species; do not turn white in 
winter. Genus SYLVILAGUS, p. 266. 
(For other characters see descriptions of Genera.) 
KEY TO THE SPECIES 
WHICH MAY OCCUR WITHIN OUR LIMITS. 
GROUP 1. Length of ear from skull to tip less than 4 inches. 
Color changes from brownish in summer to white in winter; tips of ears usually 
edged with black; nape not rufous or decidedly different in color from the 
back; total length, about 17.50 to 18.50 inches; hind foot, 5 in. (or more); 
tail vertebree, about 1.50 to 1.75 inches. Occurs in northern Wisconsin but 
not in southern Wisconsin or Illinois. 
VARYING HARE or SNOW-SHOE RABBIT. 
Lepus americanus pheonotus, p. 262. 
Rump distinctly gray or grayish, noticeably paler than back; nape usually rufous 
brown, quite different from color of back; tail vertebrae, about 2.25 to 2.75 
inches; hind foot, about 4 inches; does not turn white in winter. 
MEArNs’s CoTTON-TAIL RABBIT. 
Sylvilagus floridanus mearnsit, p. 266. 
General color brown mixed with more or less blackish; rump not distinctly gray 
or grayish; nape often tinged with rufous brown but not pronounced as in 
mearnsi,; hind foot, about 4 inches; tail, about 2.75 inches; does not turn 
white in winter. Occurs in southern Illinois but not in northern Illinois or 
Wisconsin. Swamp Rassit. Sylvilagus aquaticus, p. 271. 
GROUP 2. Length of ear from skull to tip more than 4 inches. 
Ears with black tips; tail entirely white above and below; entire length, in- 
cluding tail, usually more than 21 inches; tail, more than 3.25 inches long. 
Not as yet recorded from Illinois or Wisconsin, but stragglers may occur in 
the extreme western portion of either state. 
Jack Rassit. .Lepus campestris, p. 265. 
Genus LEPUS Linn. 
Lepus Linneus, Syst. Nat., X ed., 1758, p. 57. Type Lepus timidus 
Linneus. 
Hind legs very long; ears long; tail well developed; fore feet with 
five toes; hind feet with four toes; soles of feet covered with hair; clavicle 
imperfect; interparietal not distinct in adult; supraorbitals prom- 
inent and wing-like*; the posterior process (postorbital process) usually 
*See Fig. 2, p. 96. 
