108 NORTH AMERICANi FAUNA 66 



Figure 39. — Distribution of Pitymys pinetorum scalopsoides. 



From the southern bog lemming {Synaptomi/s cooperi) this species 

 may be readily distinguished by the lack of grooves on the upper 

 incisors. 



Measwements. — Ten adults from the District of Columbia have 

 the following external measurements: Total length 124.8 (120-131) ; 

 tail 22.1 (15-25); hind foot 16.6 (16-18). Eleven adults from the 

 District of Columbia have cranial measurements as follows: Con- 

 dylobasal length 24.9 (24.2-25.9) ; zygomatic breadth 15.5 (14.2-16.3) ; 

 interorbital breadth 4.2 (3.9-4.6) ; length of maxillary toothrow 6.1 

 (5.8-6.5). 



Habitat and hahits. — This species is not particular with regard to 

 habitat preference, being found in old fields, wood borders, and culti- 

 vated fields, especially in loose sandy soils. It is often found in old 

 apple orchards where the soil is mellow and sandy, and the grass 

 and weeds have been allowed to grow, forming a heavy protective 

 carpet of vegetation. The fallen apples also provide the mice with 

 food in autumn, and the bark of apple roots supply a favorite winter 

 food. Contrary to its name, the pine vole is seldom found in pine woods 

 in Maryland. 



Hamilton (1938, pp. 163-170) in his life history study of the spe- 

 cies says that the animal threads its way just beneath the thick carpet 

 of leaves which forms a ceiling to its burrow. Rarely the pine vole 

 tunnels to a depth of a foot or more, but by far the greater number 



