The average measurements for 29 specimens, most of them from 
this county, are as follows: Total length, 5.47 in. (139 mm.); 
tail, 1.22'in. (31 mm.); hind foot, .75-in. (19 mm.). Thereus*cen= 
siderable variation in the length of the tail, our specimens ranging 
im this respect trom 1:02 inv (26 mim: to 1.53 an GOs 
The upper parts are dark gray, with a peppery appearance due 
to the mixture of black and pale fulvous tips of long hairs, the black- 
tipped ones predominating. The sides are paler, the belly is washed 
with pale cinnamon, and the tail is bicolor. The base of the hairs 
is everywhere plumbeous. 
Kennicott regards this species as the most abundant native 
mammal on the prairie of northern Illinois. In this county I think 
that it is outnumbered on both till plains 
denne and moraines by the white-footed prairie- 
mouse, and in many localities, during the 
autumn, by the common house-mouse. _It 
CRAMAIIORD is, however, very difficult to estimate the 
number of these mice present in any area. 
prate nete name patiemo. They seem to possess the same migratory 
instinct as their near relatives, the lem- 
mings, frequently moving from place to place. At any rate, in 
common with other observers, I have often taken them in com- 
parative abundance in a locality where the year before or the year 
after not a specimen could be obtained by prolonged trapping. 
There is also a temporary shifting to grain and corn fields in fall and 
late summer, and a return to the shelter of fences, edges of woods, 
etc., in winter. Kennicott describes the species as being most 
decidedly an inhabitant of the prairie, and declares that he has never 
found it in the woods; while observers in other localities report it as 
having a most decided preference for the edge of woodlands or open 
groyes. So far as my own observation goes, it is the ground- 
cover which determines the habitat of these meadow-mice. They 
are not found in closely grazed pastures nor in well-cultivated fields 
of corn, vegetables, etc., but they may occur wherever there is a 
close growth of grass or other low vegetation. Where this condi- 
tion prevails I have taken them in groves and in fairly dense and 
extensive woods, though their favorite: situations are the waste 
places along fences, in the corners of fields, and in permanent 
pastures. They are also abundant at times in alfalfa and clover 
