1891. _Lepus idahoensis_ Merriam, N. Amer. Fauna, 5:76, July 30, type from head of Pahsimeroi Valley, near Goldburg, Custer County, Idaho (Davis, Recent Mammals of Idaho, p. 363, April 9, 1939). 1930. _Sylvilagus idahoensis_, Grinnell, Dixon and Linsdale, Univ. California Publ. Zool., 35:553, October 10. _Marginal records._--In southeastern Washington: Ritzville (Taylor and Shaw, 1929:29); Lind (243344 USBS); Warden (Taylor and Shaw, 1929:29). In remainder of range: Montana: Bannack (Davis, 1937:27). Idaho: Trail Creek near Pocatello (Davis, 1939:366). Utah: 3 mi. NE Clarkson (Durrant, MS); W side Utah Lake (_ibid._); 20 mi. W Parowan (_ibid._); 10 mi. SW Cedar City (_ibid._). Nevada: 8½ mi. NE Sharp (Hall, 1946:618); Fallon (Schantz, 1947:187). California: Bodie (Severaid, 1950:2); 5000 ft., 3 mi. S Ravendale (Orr, 1940:194). Oregon: Silver Lake (Bailey, 1936:110, fig. 17, 206518 USBS); Fremont (_ibid._, 205005 USBS); Redmond (_ibid._, 242302 USBS); 10 mi. N Baker (Dice, 1926:27). Idaho: type locality; Junction (Davis, 1939:366). Total length, 250-290; tail, 20-30; hind foot, 65-72; ear from notch (dry), 36-48; weight, 6 ♂ 409(375-435), 9 ♀ 398(246-458) grams. Upper parts pinkish to blackish or dark grayish depending on amount of wear. The pigmy rabbit lives in burrows, mostly dug by itself, preferably where tall sagebrush grows densely. This species feeds extensively on sagebrush, at least in winter. Six young seem to be the rule and they are born any time from late in May until early in August. [Illustration: FIG. 7. Distribution of _Sylvilagus idahoensis_.] Subgenus SYLVILAGUS Gray--Cottontails and Allies 1867. _Sylvilagus_ Gray, Ann. and Mag. Nat. Hist., 20 (ser. 3):221. Type, _Lepus sylvaticus_ Bachman [= _Lepus nuttalli mallurus_ Thomas]. 1867. _Tapeti_ Gray, Ann. and Mag. Nat. Hist., 20 (ser. 3):224, September. Type _Lepus brasiliensis_ Linnaeus. 1897. _Microlagus_ Trouessart, Catalogus Mammalium ..., p. 660. Type, _Lepus cinerascens_ J. A. Allen. 1897. _Limnolagus_ Mearns, Science, n. s., 5:393, March 5. Type _Lepus aquaticus_ Bachman. 1950. _Paludilagus_ Hershkovitz, Proc. U. S. Nat. Mus., 100:333, May 26. Type _Lepus palustris_ Bachman. Characters of subgeneric worth, in contrast to those of the subgenus _Brachylagus_, are: First premolar, in upper jaw and in lower jaw, with more than one fold in the enamel; infolded enamel, which divides each molar tooth into two parts, crenate.