igo Field Museum of Natural History — Zoology, Vol. XL 



Peromyscus maniculatus bairdi (Hoy & Kennicott). 



Prairie White-footed Mouse. 

 Prairie Deer Mouse. Baird's Deer Mouse. Michigan Deer 



Mouse. 



Mus hairdii HoY & Kennicott, in Kennicott, Agr. Rept. for 1856, U. S. Patent 

 Office Rept., 1857, p. 92. 



Peromyscus bairdi Snyder, Bull. Wis. Nat. Hist. Soc, II, 1902, p. 116 (Wisconsin). 

 HOLLISTER, Bull. Wis. Nat. Hist. Soc, VI, 1908, p. 40 (Wisconsin). 



Peromyscus michiganensis Jackson, Proc. Biol. Soc. Wash., XX, 1907, p. 72 (Mis- 

 souri), lb., Bull. Wis. Nat. Hist. Soc, VI, 1908, p. 21 (Wisconsin). Hahn, 

 Proc. U. S. Nat. Mus., XXXII, 1907, p. 459 (Indiana). 



Peromyscus maniculatus bairdi Hahn, Ann. Rept. Dept. Geol. & Nat. Resources 

 Ind., 1908 (1909), p. 502 (Indiana). Osgood, N. Amer. Fauna, No. 28, 1909, 

 p. 79 (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Wisconsin, etc.). 

 Howell, Proc. Biol. Soc. Wash., XXIII, 1910, p. 26 (Illinois, Missouri). 

 Wood, Bull. 111. State Lab. Nat. Hist., VIII, 1910, p. 544 (Ilhnois). 



Type locality — Bloomington, McLean Co., Illinois. 



Distribution — Prairie region of the upper Mississippi Valley in Wis- 

 consin, Illinois, Indiana, Minnesota, eastern Ohio, Iowa, Missouri, 

 Oklahoma, and eastern portions of Nebraska, Kansas, South 

 Dakota, and North Dakota; north to southern Manitoba. 



Special characters — Resembles P. I. noveboracensis but somewhat 

 smaller, tail shorter, and general color slightly darker (less brownish). 



Description — Upper parts brown, the middle of the back dark brown, 

 much darker than the sides; under parts white or whitish, the bases 

 of the hairs slaty gray, the tips white. ' When the hair is short 

 and worn, the dark bases are not entirely concealed, giving a gray- 

 ish appearance to the under parts. Upper surface of tail dark; 

 under surface pale. 



Measurements — Total length, 5.50 to 6.50 in. (140 to 165 mm.); tail 

 vertebra, 2.25 to 2.75 in. (57 to 69.5 mm.); hind foot, .70 to .75 

 in. (18 to 19 mm.). 



The Prairie White-footed Mouse is abundant in suitable localities 

 in the greater portion of Illinois and Wisconsin, and, as its name implies, 

 it inhabits dry, cultivated fields and prairies, but it also is found in 

 open woods where the growth is small and scattered. Regarding its 

 habits, I cannot do better than to quote Robert Kennicott who had 

 unusual opportunities for observing it. He says, "Not having, on the 

 prairies, the shelter found by its timber-loving cousins, in old stumps 

 and trees, this species digs burrows. These are rather simple, with 

 few or no side-passages, and often with but one entrance, the depth 

 and extent being variable, but never great. The nest is small, com- 



