2 



FARMERS^ BULLETIN 670. 



and Asia, except the southern part. In North America there are few 

 wide areas except arid deserts free from meadow mice, and in most 

 of the United States they have at times been numerous and harmful. 

 The animals are very prolific, breeding several times a season and 

 producing litters of from 6 to 10. Under favoring circumstances, not 



Fig. 1.— Field mice: a, Meadow mouse; b, pine mouse. 



well understood, they sometimes produce abnormally and become a 

 menace to all growing crops. Plagues of meadow mice have often 

 been mentioned in the history of the Old World, and even witliin the 

 United States many instances are recorded of their extraordinary 

 abundance with accompanying destruction of vegetation. 



The runs of meadow mice are mainly on the surface of the ground 

 under grass, leaves, weeds, brush, boards, snow, or other sheltering 

 litter. They are hollowed out by the animals' claws, and worn hard 

 and smooth by being frequently traversed. They are extensive, 



