Cabbage Butterfly — Chambers's Encyclopaedia

Cabbage Butterfly, a name common to several species of butterfly, the larvæ of which ('cabbage worms') devour the leaves of cruciferous plants, especially of the cabbage tribe. The Large Cabbage Butterfly, or Large White (Pieris or Pontia brassicae), is one of the commonest British butterflies. It is white, with wings tipped and spotted with black. The female is more decorative than the male. The wings, when expanded, measure from $2\frac{1}{2}$ to 3 inches across. The female lays her conical, bright yellow eggs in clusters of twenty or thirty, on the leaves of the plants which are the destined food of the caterpillars. The spring brood are found usually on wild cruciferæ; the summer set on garden vegetables. The caterpillars, when fully grown, are about 1 inch or $1\frac{1}{2}$ inch long, and are excessively voracious, eating twice their own weight of cabbage-leaf in twenty-four hours. When full grown, they suspend themselves by their tails, often under ledges of garden-walls, or similar projections, and are metamorphosed into shining pale-green chrysalids, spotted with black, from which the perfect insect emerges, either in the same season, or, in the autumn brood, after the lapse of a winter—no longer to devour cabbage-leaves, but to subsist delicately upon nectar.—The Small Cabbage Butterfly, or Small White, sometimes called the Turnip Butterfly (Pieris rapæ), very much resembles the former, but the expanse of the wings is only about 2 inches. The eggs are laid singly on the under side of the leaves of cabbages, turnips, &c., and the caterpillars, which are of a velvety appearance, pale green, with a yellow line along the back, and a yellow dotted line on each side, sometimes appear in great numbers, and prove very destructive. They bore into the hearts of cabbages, instead of merely stripping the leaves, like those of the last species, and thus are a greater pest, even when comparatively few. The chrysalis is of a pale yellowish-brown colour, freckled with black.—A third species, also common in Britain, the Green-veined White Butterfly (Pieris napi), very nearly resembles the small cabbage butterfly.—The excessive multiplication of these insects is generally prevented by small birds, which devour them and their caterpillars, also by wasps, and by insects of the Ichneumon (q.v.) tribe, which lay their eggs in the caterpillars, that their own larvæ may feed on them. As regards artificial prevention and remedies, the eggs of the large white being laid in clusters can be removed from the cabbage-leaves; the chrysalids should be sought and destroyed; various washings, dressings, and the like are useful, such as sprinklings of salt, watering with lime-water or soap-suds, and dressing the surrounding soil with soot or gas-lime; a good drenching of any kind is often advantageous. The cabbage butterfly has become naturalised in the United States, where it is very destructive. See Miss Ormerod's Injurious Insects.