26 BUTTERFLIES OF MAINE. 
mostly by night and rest by day, along in the groove of the 
midrib on the upper side of the leaf, with their heads towards 
the base of the leaf. The mature larva (Fig. 3, a), is about 
an inch and a quarter long, of a pale green color, similar to 
that of the leaves of the cabbage, with a darker line along 
the middle of the back. The entire surface is covered with 
fine, short, white hairs. When they are done feeding they 
wander off in search of some protected place, as the under 
side of a board or fence-rail, in which to change to a pupa. 
Here the larva spins a button of silk, to which the anal feet 
are attached, and a loop in which to support the forward part 
of the body. Ina short time the skin is shed, disclosing the 
pupa, which is about seven-tenths of an inch long, of a pale 
green or whitish color, and finely speckled with black. 
In summer the insect remains in this stage about a week 
or ten days, but the fall brood passes the winter in the pupa 
state. 
This species does not appear to be common in Maine, its 
place being taken by Pieris rape. For remedies, see under 
Pieris rape. 
