[Illustration: FIG. 12.]

The expanded wings, Fig. 12, male, measure about two inches, are white
above, with the base dusky. Both sexes have the apex black and a black
spot a little beyond the middle, and the female, Fig. 13, has another
spot below this. The under side of the fore wings is white, yellowish
toward the apex, and with two black spots in both sexes corresponding
to those on the upper side of the female. A little beyond the middle
of the costa, on the hind wings, is an irregular black spot on the
upper surface, while the under surface is pale lemon yellow without
marks, but sprinkled more or less with dark atoms. The body is black
above and white beneath.

[Illustration: FIG. 13.]

The caterpillars of this insect feed on the leaves of cabbage,
cauliflower, turnip, mignonette, and some other plants.

The female lays her eggs on the under side of the leaves of the food
plants, generally, but sometimes on the upper sides or even on the
leaf stalks. They are sugar loaf shaped, flattened at the base, and
with the apex cut off square at the top, pale lemon yellow in color,
about one twenty-fifth of an inch long and one fourth as wide, and
have twelve longitudinal ribs with fine cross lines between them.

The eggs hatch in about a week, and the young caterpillars, which are
very pale yellow, first eat the shells from which they have escaped,
and then spin a carpet of silk, upon which they remain except when
feeding. They now eat small round holes through the leaves, but as
they grow older change to a greenish color, with a pale yellow line