_Mustela campestris_ Jackson, Proc. Biol. Soc. Washington, 26:124, May 21, 1913. _Putorius pusillus_, Aughey, Sketches of the physical geography and geology of Nebraska, p. 119, 1880, Omaha. _Mustela rixosa campestris_, Swenk, Journ. Mamm., 7:329, Nov. 23, 1926. _Type._--Female, adult, skin and skull; no. 171490, U. S. Nat. Mus., Biol. Surv. Coll.; Beemer, Cuming County, Nebraska; April 18, 1911; obtained by G. Sharp; x catalogue no. 8440. The skull is unbroken. On the left side, C1 and P2 are missing; the other teeth are present and entire. The skin is excellently made and in a good state of preservation. _Range._--South Dakota, Nebraska and Iowa. See figure 28 on page 180. _Characters for ready recognition._--Differs from _M. r. rixosa_ and _M. r. allegheniensis_ in larger size: Hind foot more than 25 in males and ordinarily more than 22 in females; in males total length more than 216 and tail averaging more than 34; color possibly slightly paler than in _M. r. rixosa_ and averaging paler than in _M. r. allegheniensis_; from _M. frenata_ and _M. erminea_ of the same region by basilar length less than 32; tail less than 50, and lacking black pencil. _Description._--_Size._--Male: Four adults from Nebraska yield average and extreme measurements as follows: Total length, 231 (225-237); length of tail, 36 (32-39); length of hind foot, 29 (28-31). Female: Six adults from Nebraska yield average and extreme measurements as follows: Total length, 192 (184-225); length of tail, 35 (28-40); length of hind foot, 23 (20.5-26). _Color._--Winter pelage ordinarily white; as described in _M. r. eskimo_ except possibly paler and certainly with line of demarcation on side of head between upper parts and underparts passing almost straight back without the dorsally directed reëntrant angles of white behind the eye and ear; least width of color of underparts in four specimens from Nebraska averaging 80 (49-89) per cent of greatest width of color of upper parts, but in a fifth animal in summer pelage the brown color of the upper parts encircles the body. _Skull._--See measurements in table and plate 15; weight 1.1 grams (male from Brown Co., S. D.); basilar length, 30.7 in male from Clay Co., Neb., and 28.8 in female from same county; otherwise as described in _M. e. richardsonii_. _Remarks._--In his revisionary treatment of the American races of _Mustela rixosa_, Myron H. Swenk (1926:313) credits Samuel Aughey with recording this animal, _M. r. campestris_, from Nebraska, as early as 1880, under the name _Putorius pusillus_. In 1908, Swenk recorded the animal from the same state under the name _rixosus_ and in 1913 the race _campestris_ was formally named by H. H. T. Jackson.