PREFACE. 



The present work includes, so far as known, all the living mammals 

 which have been found in Illinois and Wisconsin, and gives descriptions 

 of the various species and subspecies, with more or less of their life 

 histories, together with maps illustrating their supposed geographical 

 distribution. To increase its usefulness, brief synopses of all the known 

 species and subspecies, belonging to our genera, which occur in eastern 

 North America, are given and their distribution is indicated in the maps. 



While it is hoped it will prove a useful book of reference for the 

 specialist, it has been written with special regard to the needs of the 

 layman, for, without departing from scientific lines, I have endeavored 

 to make it as non-technical and popular in character as a serious con- 

 sideration of the subject would permit. 



With this object in view, for the purpose of simplifying identifica- 

 tion of the various species belonging to a family, they are, wherever 

 possible, arranged in the keys in groups based upon external characters 

 which may be readily recognized by the lay reader, often regardless of 

 their genera and not serially in their proper order as they are treated 

 in the text. In a few cases, however, positive identification of a species 

 depends upon dental characters which, while usually well-marked, are 

 sometimes (as among the Shrews) too small to be seen with the naked 

 eye. The student should therefore provide himself with a strong lens 

 for the purpose. 



At the present time 94 species and subspecies of mammals have 

 been recorded from Illinois and Wisconsin, and probably several more 

 will in time be added to the list. Such species as Dyche's Harvest 

 Mouse {Reithrodontomys dychei), Little Meadow Mouse (Microtus 

 minor), Woodland Jumping Mouse (NapcBozapus insignis), Prairie Spot- 

 ted Skunk {Spilogale interrupta) , Big-eared Bat {Corynorhinus macrotis) 

 and Free-tailed Bat {Nyctinomus depressus), have been taken in 

 such nearby localities that there is little doubt that most of them will 

 ultimately be found to occur within our limits. 



Those who desire to study our mammals will be interested to learn 

 that a considerable number may still be found in a wild state in 

 the public parks of Chicago. In Jackson Park alone I have seen the 

 following fifteen species: Northern Gray Squirrel, Striped Ground 



