THE PIERINAE
This is the subfamily of the small and medium-sized butterflies, white and yellow in color, so common about pastures and roadsides. Pieris rapae, the cabbage butterfly, is one of the most familiar species. It is a white butterfly, with one or two black dots and tips on the fore wings. The pale yellow eggs are deposited on cabbage plants; the smooth green caterpillar eats an enormous amount of sauerkraut material, and turns into a gray or brownish chrysalis. This butterfly was originally a European species; imported through some accident, it appeared in Quebec about 1860. As early as 1868 it was common about New York, and by 1881 had spread to all of the eastern states. In 1886 it was reported from Denver, and has since taken possession of cabbage-fields in every part of the country.
Fig. IV.—The Zebra Swallowtail (Papilio ajax), a typical representative of the subfamily Papilioninae. A, egg; B, mature larva; C, pupa or chrysalis (note the silken girdle); D, imago or adult.
Colias philodice, the Common Yellow, is the butterfly seen swarming about roadside mud-puddles in August and September. The wings are lemon color with black borders, and in the female the borders are usually broken by several small yellow spots. The yellow or reddish eggs are laid upon various kinds of clover; the slender green caterpillar is exactly the color of the leaves; the chrysalis is usually pale green also. This butterfly is found from New England to Florida, and as far west as the Rocky Mountains.
Terias lisa is another yellow butterfly, much smaller than Colias philodice, rarely expanding more than an inch and a quarter. The wings are lemon yellow with black borders, subject to many minor variations. The caterpillar feeds on clover, but the early stages of this species have never been thoroughly studied, despite the fact that the butterfly is common from the New England states to the Rockies.
Terias mexicana, the Mexican Yellow, is larger than Terias lisa, and somewhat paler in color. The black borders or the fore wings are very wide and indented, and the hind wings are pointed. Very little is known of its early stages. It is common in Texas, Arizona, and Southern California, and often strays much farther north. I have myself taken a number of specimens in Kansas.