Early Stages.—The food-plant is clover. The eggs are pale yellow, changing, after being laid, to crimson. The caterpillar is slender, green, striped longitudinally with paler green. The chrysalis is pale green.
The species ranges from New England to Florida, and westward to the Rocky Mountains.
(5) Colias chrysomelas, Henry Edwards, Plate XXXV, Fig. 12, ♂; Fig. 13, ♁ (The Gold-and-black Sulphur).
Butterfly.—Larger than C. philodice. The male on the upper side is bright lemon-yellow, with broad black margins on both wings. The female is paler, with the black margin of the hind wing lacking or very faintly indicated, and the margin of the fore wing much broken up by yellow spots. On the under side the wings of the male are dusky-orange, pale yellow on the disk of the primaries; the wings of the female on this side are pale yellow. Expanse, ♂, 2.00-2.10 inches; ♁, 2.25-2.30 inches.
Early Stages.—Undescribed.
The home of this species is on the Coast Range of northern California.
(6) Colias alexandra, Edwards, Plate XXXV, Fig. 6, ♂; Fig. 7, ♁ (The Alexandra Sulphur).
Butterfly.—Larger than C. philodice. The male is pale canary-yellow, with much narrower black borders than the preceding species. The female is pale yellow or white, without black borders, or, at most, faint traces of them at the apex of the primaries. On the under side the wings are silvery-gray, yellow only at the base and on the inner margin of the primaries. The discal spot on the hind wings is white. Expanse, ♂, 1.85 inch; ♁, 2.10-2.30 inches.
Early Stages.—The caterpillar is uniformly yellowish-green, with a white band on each side, broken with orange-red dashes running through it. The chrysalis, which resembles that of C. philodice in form, is yellowish-green, darkest on the dorsal side, and adorned with three small red dots on the ventral side of the abdomen near the wing-cases. The caterpillar eats Astragalus, Thermopsis, and white clover. Expanse, ♂, 1.90-2.15 inches; ♁, 2.00-2.30 inches.
The species is found in Colorado and the mountain regions to the north and west of that State.