10 CONTENTS 



Part II. Keys to the Suborders, Families, Genera and 



Species of Iowa Rodents 141 



Order Rodentia, Gnawing Mammals 141 



Key to Suborders of Rodentia 141 



Suborder Simplicidentata 141 



Key to Families of Simplicidentata 142 



Family Sciuridse, Squirrels, Woodchucks, etc 142 



Key to the Genera of Sciuridse 142 



Subfamily Pteromyinse , 143 



Genus Glaucomys 143 



Glaucomys volans volans. Southern Flying 



Squirrel 143 



Subfamily Sciurinse 143 



Genus Sciurus 143 



Key to Species of Sciurus 143 



Sciurus carolin3nsis leucotis, Northern Gray 



Squirrel 143 



Sciurus niger rufiventer, Western Fox Squirrel 143 



Sciurus hudsonicus loquax, Red Squirrel 143 



Genus Tamias 144 



Key to species of Tamias 144 



Tamias striatus striatus, Chipmunk 144 



Tamias striatus griseus, Gray Chipmunk 144 



Subfamily Marmotina; 144 



Genus Citellus 144 



Key to Species of Citellus 144 



Citellus franklini, Franklin's Spermophile 144 



Citellus tridecemlineatus tridecemlineatus, 



Thirteen-lined Spermophile 144 



Genus Cynomys 145 



Cynomys ludovicianus ludovicianus. Black- 

 tailed Prairie-dog 145. 



Genus Marmota 145 



Marmota monax monax, Southern Woodchuck 145 



Family Castoridse, Beavers 145 



Genus Castor 146 



Castor canadensis canadensis, Beaver 146 



Family Muridse, Rats and Mice 146 



Key to the Genera of Muridse 146 



Subfamily Murinse 147 



Genus Mus 147 



Mus musculus, House Mouse 147 



Genus Rattus 147 



Key to Species of Rattus 147 



Rattus norvegicus. Brown Rat 147 



Rattus rattus, Black Rat 14? 



Subfamily Cricetinse l'»<^ 



Genus Peromyscus 148 



Key to Species of Peromyscus • 148 



