3 o6 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



the constant rubbing on each other. The food of rodents is 

 chiefly vegetable. 



The order is divided into several families of which the fol- 

 lowing are the most common: the Leporida, the rabbits and 

 hares; the Erethizontida, the porcupines; the Geomyida, the 



FIG. 134. Chipmunk. (Permission of Camera Craft.) 



pocket gophers; the Zapodidce, the jumping mice; the Dipodida, 

 the pocket mice and kangaroo rats; the Murida, the mice and 

 rats; the Castorida, the beavers; and the Sciurida, the squir- 

 rels, woodchucks and prairie-dogs. 



Of the hares and rabbits, the cottontail, Lepus sylvaticus, and 



