576 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
The following synoptical arrangement may serve to facilitate the determination of our species 
of hares: 
A.— Skull with distinct post-orbital processes. 
a. Hind feet considerably longer than the head; size of body large. 
I. Post-orhital processes widely divergent, hounding a notch. The 
American species change to white in winter. 
Ears about as long as the head, or less. Tail short. 
1. Very large. In summer, sooty yellowish gray. Ears with black tip on 
both surfaces. In winter, fur pure white to roots. L. gladalis■. 
2. In summer, cinnamon brown. Tail sooty above. Ears with most of dorsal 
surface whitish. Winter under fur lead colored at base, then brownish 
red. L. americanus. 
3. Smaller. In summer, rich cinnamon. Tail brownish above. Ears with 
dorsal surface, light cinnamon, and with a good deal of black. Pads of 
the toes abruptly lighter than those of the metatarsus. L. washingtonii. 
Ears considerably longer than the head ; tail long. 
4. In summer, yellowish brown gray. Tail white on both surfaces ; as long 
as the head. Winter, under fur white at the base, then reddish. L. campestris. 
II. Post orbital processes divergent, but in contact behind by their extremi¬ 
ties with the cranium. Tail black above, this color running up on 
the rump. 
5. Above, yellowish gray and black; rump ashy ; tail and body beneath, 
whitish... L. callotis. 
6. Above, cinnamon, red, and black; rump not dissimilar. Under surface of 
tail and body light cinnamon. L. californicus. 
b. Hind feet nearly the length of the head. Size medium; inner edge of post¬ 
orbital processes united behind and laterally by suture with the cranium. 
I. Soles very densely furred; fur on back, with two yellowish subterminal 
brown bars, enclosing a dusky one. Tail two-thirds as long as the ear. 
7. Skull nearly 3 inches long. Ears shorter than the head. Above, yellowish 
brown, with a tinge of reddish. L. sylvaticus. 
8. Smaller. Skull about 2.65 inches long. Ears as long as the head. Above, 
grayish yellowish brown..... L. artemisia. 
II. Soles rather scantily furred; fur on back, with only one yellowish 
brown bar, external to a blackish one. 
9. Tail very short; scarcely half the length of the ear.... L. bachmanii. 
c. Hind feet apparently shorter than the head. Post-orbital processes scarcely 
in contact with the cranium behind. 
Ears nearly as long or longer than the head. 
10. Tail long. Fur on back, with only one yellowish brown subterminal bar. L. audubonii. 
11. Tail very short. Fur on back, with two subterminal yellowish brown 
bars enclosing a dusky one. . L. trowbridgii. 
