2 PREFACE 



Squirrel or "Gopher," Northern White-footed Mouse, Meadow Mouse, 

 Muskrat, House Mouse, House Rat or Norway Rat, Cotton-tail Rab- 

 bit, Mink, Common Shrew,* Short-tailed Shrew,* Prairie Mole,* 

 Silver-haired Bat,* Red Bat,* and Hoary Bat.* In addition to these 

 there is a specimen of the Raccoon in this Museum, which was 

 killed in Jackson Park in 1898, and I am informed that Chipmunks, 

 a Skunk and a Weasel have been seen. 



In preparing the present work the majority of specimens examined 

 are in the collection of the Field Museum of Natural History; but in 

 addition to these a large number were loaned to me by other Museums 

 and private collectors. In this connection I wish especially to express 

 my thanks to Dr. C. Hart Merriam and Mr. H. W. Henshaw, U. S. 

 Biological Survey, Washington; Dr. J. A. Allen and Mr. Roy C. An- 

 drews, American Museum of Natural History, New York; Mr. Outram 

 Bangs, Museum of Comparative Zoology, Cambridge; Mr. Gerrit S. 

 Miller, Jr., National Museum, Washington; Mr. Witmer Stone, Acad- 

 emy of Natural Sciences, Philadelphia; Mr. H. L. Ward, Milwaukee 

 Public Museum; Dr. H. V. Ogden, Milwaukee; Dr. B. H. Bailey, Coe 

 College Museum, Cedar Rapids, Iowa; and Mr. W. E. Snyder, Beaver 

 Dam, Wisconsin. 



In the lists of specimens examined those not contained in the Field 

 Museum collection are indicated as follows: (N. M.) U. S. National 

 Museum; (B. S.) U. S. Biological Survey; (A. M.) American Museum 

 of Natural History; (M. C. Z.) Museum of Comparative Zoology; 

 (I. S. L.) Illinois State Laboratory of Natural History, Urbana; (M. P. 

 M.) Milwaukee Public- Museum; (O. C.) Collection of Dr. H. V. 

 Ogden, Milwaukee; (S. C.) Collection of Mr. W. E. Snyder, Beaver Dam, 

 Wisconsin; (O.) from other sources, special mention of which is usually 

 made in the text. In all other cases the names of individuals or in- 

 stitutions from which the specimens were received are given in full. 



Practically all of the original drawings for the halftones and many 

 of the zinc-etchings are the work of Mr. Leon L. Pray; and the maps 

 and nearly all the cuts of teeth, feet, etc., were carefully drawn by Mr. 

 A. B. Wolcott. 



In conclusion, it is a pleasure to express- my appreciation of the kind 

 assistance of Mr. William J. Gerhard, Assistant Curator of Entomol- 

 ogy in this Museum, in reading proof, preparing the index and constantly 

 aiding me in many ways which materially lessened my labor. 



November i, 1911. CHARLES B. CORY. 



* Found dead or trapped. 



