Occasional Papers of the Museum of Zoology 15 



February 13, 1903, E. H. Frothingham found one under a 

 corn shock about four miles south of Ann Arbor. In a run- 

 way in a small tamarack stand in Steere's Swamp, near the 

 same place, I trapped an adult female and four nearly grown 

 young, October 8 and 9, 1903. In February, March, and April, 

 1 92 1, H. B. Sherman trapped six in a field containing a little 

 brush, a short distance south of Ann Arbor. A number of 

 their remains were found by J. Van Tyne in the winters of 

 1921 and 1922 near Ann Arbor, in pellets of the long-eared 

 owl. 



Microtns petwsylvanicus pennsylv aniens. Pennsylvania Vole. 

 — Was formerly found in beaver meadows, but with the clear- 

 ing of the forests it has extended its range to the fields of 

 grass and grain, and has become the most numerous of all 

 the mammals of the county. Records are at hand for Ann 

 Arbor, Pittsfield Township, and Portage Lake. 



Micro\tus pinetornm scalopsoides. Pine Vole. — July 15, 1921, 

 A. G. Ruthven found an adult male in the oak-hickory woods 

 on his grounds near the outskirts of Ann Arbor. 



Fiber zibethicus zibethicus. Muskrat. — In spite of persistent 

 trapping, muskrats are still numerous in the county. Records 

 are at hand for Ann Arbor, Pittsfield Township, Portage Lake, 

 Saline, and Ypsilanti. 



Rattus norvcgicus. Norway Rat. — This injurious rodent 

 became common soon after the settlement of the county. Its 

 omnivorous food habits and adaptability have enabled it to 

 increase greatly. 



Mus niHSculus museulus. House Mouse. — The house mouse 

 did not reach Washtenaw County until several years after the 

 settlement of the district. It has become a serious pest, not 

 only to household efifects and stored food, but it has taken to 



