(7) Colias interior, Scudder, Plate XXXV, Fig. 10, ♂; Fig. 11, ♁ (The Pink-edged Sulphur).
Butterfly.—The male on the upper side closely resembles C. philodice, but is smaller, the fringes of the wings rose-colored. The female is pale yellow above, more frequently white, with the tips of the fore wings lightly marked with blackish. On the under side the fore wings at the apex and the entire surface of the hind wings are rusty orange-yellow. The discal spot on the hind wings is silvery, bordered with rosy-red. Expanse, ♂, 1.30-1.75 inch; ♁, 1.60-2.00 inches.
Early Stages.—Little is as yet known of these.
The species was first found by Professor Louis Agassiz on the north shore of Lake Superior. It ranges through a rather narrow belt of country, through Quebec, Ontario, and westward to the Rocky Mountains north of the valley of the St. Lawrence and the Great Lakes.
(8) Colias scudderi, Reakirt, Plate XXXV, Fig. 8, ♂; Fig. 9, ♁ (Scudder's Sulphur).
Butterfly.—The male on the upper side is colored like C. philodice, but the black borders are much wider. The fringes are rosy. The female is generally white,—very rarely slightly yellow,—with very pale dark borders, or often without any trace of black on the outer margin of the wings. On the under side the apex of the fore wings and the entire surface of the hind wings are greenish-gray. The discal spot of the secondaries is well silvered and margined with pale red. Expanse, 1.80-2.00 inches.
Early Stages.—We know but little of these, except that the caterpillar feeds on the leaves of the huckleberry and the willow.
Scudder's Sulphur is found in Colorado, Utah, Montana, and British Columbia.
(9) Colias pelidne, Boisduval, Plate XXXV, Fig. 14, ♂; Plate XXXVI, Fig. 15, ♂; Fig. 16, ♁ (The Labrador Sulphur).