Although this species is at times so abundant that it swarms in great flocks and although it has been known for many years, its life-history seems not to have been carefully worked out since it was first described by Abbott more than a century ago. The caterpillars feed upon cruciferous plants and when full grown are about an inch and a half long, of a general yellow color, more or less striped with purple lines. The species is distinctly tropical extending northward into our Southern states.
Dr. G. B. Longstaff reports this species as abundant in Jamaica where he found that the clubs of the antennae of the living insects showed a beautiful turquoise blue color, although another observer described them as bright green with a tinge of blue. This is an interesting color variation for a member of this group. In the tropics also there are two forms, one belonging to the dry season and one to the wet season.
Imported Cabbage Butterfly (Pieris rapae). Expanse 2 inches. Upper surface white with a black marginal dash on the front outer angle of the front wing. One round black spot on each of the four wings in the male. Two round spots on each of the front wings in the female and one round spot on each of the hind wings. Under surface of hind wings yellowish white; spots on front wings in same position as on upper surface. A spring form (immaculata) is smaller and the black spots are almost obsolete.
Gray-veined White (Pieris napi). Expanse 2 inches. Upper surface white with only a darker marginal splash next the body. Under surface white with gray veins.
Checkered White (Pontia protodice or Pieris protodice). Expanse 2 inches. Upper surface white, strongly marked especially in the female with dark grayish brown on both pairs of wings. Along the outer margins these marks are so arranged as to enclose white diamond spots. Male with front wings only lightly marked and hind wings scarcely marked at all. Under surface much like upper, with a slight yellowish tinge in female.
Great Southern White (Pontia monuste or Pieris phileta.) Expanse 2½ inches. General color white with a narrow black margin around apical angle of front wings. These margins are wider in the female, in which sex there is a series of marginal spots on the hind wings. Easily known by its large size.
When one sees a gossamer-winged butterfly flitting from flower to flower on a bright June day it seems one of the most ethereal of earth's visions. One could readily fancy that the whole sight—flowers, butterflies, and all—might easily vanish into thin air. So it is something of a shock to hear scientists talk about fossil butterflies and to realize that these fragile creatures have been living generation after generation for untold millions of years. A realization of this fact, however, helps us to understand the many wonderful ways in which butterflies in all stages of their existence have become adapted to the conditions of their lives.
There is perhaps no group of butterflies whose beauty seems more fragile than that of the Orange-tips. These are delicate creatures, with slender bodies and almost gauzy wings, of a size somewhat smaller than our common white and yellow butterflies. Perhaps the most remarkable feature is the marking of the wings, the upper sides of the front pair having an orange patch near the apex and the under sides having a background of delicate whitish or yellowish green, lined and spotted with darker coloring in a very characteristic way. This peculiar marking is so significant that it has been called "flower picturing." To understand the reason for its existence one has only to watch the butterflies in their native haunts. He will find them flitting from blossom to blossom among the plants of the mustard family—the Cruciferae. This is one of the most characteristic families in the plant world: the foliage for the most part is small and delicate and the flowers have a characteristic four-petaled structure, being practically always of small size and generally toned in whites or yellows. When an Orange-tip is at rest upon these blossoms it merges so completely into the background that it disappears from view. Should a bird chase one of these insects through the air it would see chiefly the orange tips which are so marked upon the upper side of the wing, and when the butterfly closed its wings and lighted among the flowers the orange color would instantly disappear and there would be only an almost invisible surface against the background of flower and leaf.