539 
often catch but little else. There seems to be an irruption of these 
mice into the field after the crop is cut. Traps set under shocks 
just put up will catch none of the mice, except perhaps near a 
barn or other shelter, but later the mice may be taken under 
shocks farther and farther out in the field, and within a fortnight 
they may be found in the center of an eighty-acre lot. As noted 
on page 505, they apparently drive the white-footed prairie-mouse 
away from the shocks. During most of the year house-mice are 
not commonly found in the woods or open fields except under 
some sort of artificial shelter. It is curious to note how a refuse 
dump, a compost heap, a pile of old boards, a haystack— what- 
ever is the work of man’s hands or the remains or refuse of his 
habitations—attracts these mice. In the middle of an extensive 
sand area in Mason county a few bits of boards and a bushel or two 
of old tin cans and broken pottery gave shelter to a colony of house- 
mice, though a full half mile from anything else that could have 
protected them. Bailey reports finding them in Texas on a de- 
‘serted ranch a hundred miles from the nearest railroad town.* 
There is considerable variation in color in this species within the 
county. The general mouse-gray is usually modified to a greater 
or less degree by a flush of orange-yellow—‘‘varying through smoke- 
gray and drab-buff to near orange-buff.’’ One gets all these varia- 
tions in a single locality and among specimens taken on the same 
date. I have not been able to correlate these variations with any 
ecological factor. 
WHITE-FOOTED WOOD-MOUSE. 
Peromyscus leucopus noveboracensts (Fischer). 
(Osgood, N. Am. Fauna, No. 28, 1909, p. 117.) 
Mus sylvaticus noveboracensis Fischer, Synop. Mamm., 1829, p. 318. 
Mus leucopus (Raf.), Kennicott. 
The range of this subspecies is from Nova Scotia to central Min- 
nesota, thence south through the humid parts of eastern Nebraska 
and Kansas, and eastward to the Atlantic coast. 
There is considerable variation in size, as shown by the following 
table. 
cON eam. Mauna, No: 25, p. 92. 
