Part 14 (1/2)
5'. Ear from notch less than 82 dry (87 fresh); least interorbital breadth less than 26 _Lepus america.n.u.s_, p. 173
2'. Brownish or grayish pelage.
6. Tail blackish or brownish all around (in specimens not having completed molt on tail, white winter pelage may be present); basilar length less than 67 mm.
_Lepus america.n.u.s_, p. 173
6'. Tail partly or wholly white.
7. Tail black on upper surface.
8. Upper sides of hind feet without a trace of white; upper parts tawny.
_Lepus europaeus_, p. 189
8'. Upper sides of hind feet with more or less white or whitish; upper parts grayish or brownish _Lepus californicus_, p. 181
7'. Tail all white or (in some _Lepus townsendii_) with faint buffy or dusky median line on top but this line not extending on to rump (as in _L. californicus_).
9. Geographic range north of a line from Port Simpson, British Columbia, to Halifax, Nova Scotia.
10. Geographic range east of Mackenzie River _Lepus arcticus_, p. 178
10'. Geographic range west of Mackenzie River _Lepus othus_, p. 177
9'. Geographic range south of a line from Port Simpson, British Columbia, to Halifax, Nova Scotia _Lepus townsendii_, p. 180
1'. South of 34 N lat.i.tude.
11. In state of Tamaulipas, Mexico.
_Lepus californicus_, p. 181
11'. Range outside Tamaulipas, Mexico.
12. Ears with terminal black patch (on outside).
_Lepus californicus_ and _Lepus insularis_, pp. 181, 186
12'. Ears without terminal black patch.
13. Ear from notch, dry more than 130 (137 fresh), _Lepus alleni_, p. 188
13'. Ear from notch, dry less than 130 (137 fresh).
14. Nape more or less black.
15. Ears yellow; range Pacific Coastal region of Isthmus of Tehuantepec in southern Oaxaca and Chiapas.
_Lepus flavigularis_, p. 188
15'. Ears dark buff, grayish, white and black; range north of Isthmus of Tehuantepec.
_Lepus callotis_, p. 186