2 
oblong spot and the lateral margin, and the distal ends of the veins are 
often colored with a small triangular spot of black. The hind wings are 
plain white. The female has, in addition to the spots of the male, a bor- 
der of black spots on the latera] margin of the front wings. All the 
black spots are usually larger, and the base of the wing is usually dark- 
ened. The hind wings have a border of dark enclosing poorly-defioed 
lozenge-shaped white spots. In the male, the under side of the front 
wings resembles the upper, but is usually more pale. The under side 
of the hind wings is white, sometimes yellowish or greenish. There is 
usually a dark spot near the center of the wing, and a few poorly defined 
spots near the margin. In the female the under side of both wings is 
tinged along the veins with yellowish or greenish-brown. The front 
wings have pale spots corresponding to those on the upper surface, except 
the marginal ones, and the hind wings are often plain white with a yel- 
lowish cast. This species is subject to even greater variation than P. 
rape. 
The cabbage butterflies hibernate as chrysalids or pupe. 
They are fastened to walls, outhouses, fences and trees in the 
vicinity of fields or gardens where cabbages grew during the 
season. Their form is shown in the illustrations. The cater- 
pillars, in selecting quarters for pupation, prefer a perpendicular 
object protected from rain and snow. For this reason, the 
largest number of chrysalids are found under the top-boards of 
fences. The caterpillar, before throwing off its last skin and 
assuming the form of a pupa, spins a silken carpet upon the 
object that it has selected for this purpose, and into this carpet 
presses the pointed tail of the pupa. To prevent them from 
falling, during this performance, the caterpillars spin silken 
loops supporting the middle part of their bodies. The chry- 
salids remain in this position all winter and, as they are well 
protected by their color and markings, which resemble wood, 
they are not readily found by their enemies. Still a large 
number of those seeking shelter near the ground are discov- 
ered by their furred and feathered enemies. Among the former 
we have such beneficial animals as shrews, which, prompted 
by the scarcity of food in winter, investigate most carefully 
all places that might contain insects; and as they discover 
such food not by sight but by smell,even more perfect mimicry 
of the chrysalids would prove of no avail. The birds that 
pass the winter in Minnesota are chiefly seed-eating birds 
and these kill but few pup; however, as soon as spring 
approaches, large numbers of truly insectivorous birds, as 
