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 Zodlogy, 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 Zodlogy; 
(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 1, rg11. Cuar_es B. Cory. 
* Found dead or trapped. 
