512 



REPORT OF STATE GEOLOGIST. 



farm of the mice is to keep it free from rank grass, weeds or bushes. 

 They are easily caught in traps set in their runways and baited with 

 dry oatmeal, nuts, cheese or even bread or grain. Occasionally 

 they damage orchards by stripping the bark from the young trees 

 in winter. However, the prairie vole is not the worst offender in 

 this respect. 



MIGROTUS PINETORUM AURICULARIS Bailey. 



BLUE-GRASS VOLE. 



Microtus pinetorum auricularis Bailey, Proc. Biol. Soc. Wash- 

 ington, Vol. XII, p. 90, 1898. N. Am. Fauna, No. 17, p. 65, 

 1900. 



Arvicola pinetorum Evermann and Butler (part), Proc. Ind. 

 Acad. Sci. for 1893, p. 127. 



Diagnostic characters. — Distinguished from all the other mice 

 of this family except Synaptomys by its short tail (less than one 

 inch). From Synaptomys it is distinguished by being brown in 

 color instead of gray, and in having slender upper incisors without 

 grooves down the front. 



Description. — The chief difficulty in identifying this mouse is 

 in separating it from the next subspecies to which it is closely re- 

 lated and the two forms are therefore compared here, the char- 

 acters being taken principally from Bailey. Upper parts dull 

 brownish chestnut in scalopsoides, not always darker, but always 

 richer and more intense in auricularis; tail indistinctly bicolor in 

 scalopsoides, being sooty above and grayish below; scarcely darker 

 above than below in auricularis. Feet brownish gray in scalop- 

 soides; dull brown in auricularis. Ears scarcely visible above the 

 fur in scalopsoides; distinctly projecting in auricularis. Average 

 measurements of scalopsoides from the type locality (Long Island, 

 New York), total length, 125 mm.; tail, 20 mm.; hind foot, 16.3 

 mm. ; of auricularis from the type locality (Washington, Missis- 

 sippi), total length, 119 mm.; tail, 22 mm.; hind foot, 17 mm. 

 The skull is also slightly larger and the tooth row longer in scalop- 

 soides. 



The fur of these mic(i is soft and vc^lvety and there are no coarse 

 hairs. Th(Mr eyes are nlso smaller than those of tlie two preceding 

 species, and they are l)etter adapted to tlu; uTid(;rgr()nnd life, which 

 lliey s(!(!rn to [yrofvr. Thi'j-o iwo but two f)airs of m;urim;ie, l)oth in 

 1h(^ inguinal region. 



Specimens from Bascom, Mitchell and Bicknell have been as- 



