150 FIELD MUSEUM or NATURAL HISTORY ZOOLOGY, VOL. XL 



Cynomys ludovicianus (ORD), PRAIRIE DOG. Thomas includes 

 this species in his list of Illinois Mammals (1. c., p. 657.) but it is 

 probably an error, as the eastern limits of the range of this species is 

 much farther west, it being rarely found east of the Missouri River.* 



Genus MARMOTA Blum. 



Marmota Blumenbach, Handb. der Naturg., I, 1779, p. 79. 



Size large, weight 8 to 10 pounds, but more often less; general color 

 grizzly brown or grayish brown, without stripes; skull broad and de- 

 pressed; post-orbital processes long and pointed; first premolar nearly 

 as large as second; infraorbital foramen confined to lower part of 

 maxillary; edges of auditory meatus somewhat protruding; tail com- 

 paratively short (5 to 6 inches) and thickly haired; front feet with four 

 developed toes and a rudimentary thumb ; hind feet with five toes. 

 Six species and two subspecies are recognized in North America, but 

 only one species and one subspecies occur within our limits. 



Dental formula: I. - --> C. > Pm. > M. $^= 22. 



i-i o-o i-i 3-3 



KEY TO OUR SPECIES. 



A. Larger, with less rusty brown on under parts. Occurs in Illinois and Wisconsin. 



WOODCHUCK. Marmota monax, p. 150. 



B. Smaller, with more rusty brown on under parts. Occurs in extreme northern 

 Wisconsin. CANADA WOODCHUCK. Marmota monax canadensis, p. 157. 



^ Marmota monax (LINN.). 

 WOODCHUCK. GROUND HOG. 



[Mtts] monax LINNAEUS, Syst. Nat., X ed., I, 1758, p. 60. 



Arctomys monax LAPHAM, Trans. Wis. State Agr. Soc., II, 1852 (1853), p. 339 

 (Wisconsin). KENNICOTT, Trans. 111. State Agr. Soc., I, 1853-54 ( l8 55)t P- 

 579 (Cook Co., Illinois). Ib., Agr. Kept, for 1856, U. S. Patent Office Rept., 

 1857, p. 82 (Illinois). MILES, Rept. Geol. Surv. Mich., I, 1860 (1861), p. 221 

 (Michigan). ALLEN, Proc. Bost. Soc. Nat. Hist., XIII, 1869 (1871), p. 190 

 (Iowa). OSBORN, Proc. Iowa Acad. Sci., I, 1887-89 (1890), p. 43 (Iowa). 

 STRONG, Geol. Wis., Surv. 1873-79, I. l8 83, p. 440 (Wisconsin). HERRICK, 

 Geol. & Nat. Hist. Surv. Minn., Bull. No. 7, 1892, p. 168 (Minnesota). GARMAN, 

 Bull. Essex Inst., XXVI, 1894, p. 6 (Kentucky). RHOADS, Proc. Acad. Nat. 

 Sci. Phila., 1896 (1897), p. 193 (Tennessee). MILLER, Proc. Bost. Soc. Nat. 

 Hist., XXVIII, 1897, p. 26 (Milton, Ontario). EVERMANN & BUTLER, Proc. 

 Ind. Acad. Sci., 1893 (1894), p. 128 (Indiana). SNYDER, Bull. Wis. Nat. Hist. 

 Soc., II, 1902, p. 120 (Wisconsin). 



* Pellett records it from Cass County, southwestern Iowa. (Proc. Iowa Acad. 

 Sci., 1910, p. 214.) 



