Caterpillar.—The caterpillar has been carefully studied, and its various stages are fully described in "The Butterflies of New England," by Dr. Scudder. In its final stage it is about seven eighths of an inch long, dark olive-brown, marked with green, the segments being adorned with fleshy tubercles armed with needle-shaped projections, the tubercles on the side of the first thoracic segment being four times as long as the others, cylindrical in form, and blunt at the upper end, the spines projecting upward at an angle of forty-five degrees to the axis of the tubercle.
Chrysalis.—The chrysalis is yellowish-brown, spotted with darker brown spots, those of the thoracic and first and second abdominal segments having the lustre of mother-of-pearl.
This very pretty little species has a wide range, extending from New England to Montana, from Nova Scotia to Alaska, and southward along the ridges of the Alleghanies into Virginia and the mountains of North Carolina.
(2) Brenthis triclaris, Hübner, Plate XV, Fig. 3, ♂ (Hübner's Fritillary).
Butterfly, ♂.—The male above is bright fulvous, with the base of the fore wings and the inner margin of the hind wings heavily obscured with blackish scales. The usual dark markings are finer than in the preceding species; the black marginal borders are not so heavy. The submarginal spots are relatively large and distinct in most specimens, and uniform in size. The light spots of the under side of the median band of the hind wings show through from below on the upper side lighter than the ground-color of the wings. On the under side the fore wings are fulvous, tipped with ferruginous. The hind wings are broadly ferruginous, with a couple of bright-yellow spots near the base and a curved band of yellow spots crossing the median area. The outer margin about the middle is marked with pale fulvous. The spots on the under side are none of them silvered.
♁.—The female is much paler than the male in most cases, and the marginal spots within the lunules are very pale, almost white. The submarginal row of round black spots is relatively large and distinct, quite uniform in size. On the under side the wings are much more conspicuously marked on the secondaries than in the male sex, being crossed by three conspicuous bands of irregularly shaped yellow spots, one at the base and one on either side of the discal area. The submarginal round spots of the upper side reappear on the under side as small, slightly silvered, yellow spots. The marginal spots are bright yellow, slightly glossed with silver. Expanse, ♂, 1.50 inch; ♁, 1.60 inch.
Early Stages.—Unknown.
This extremely beautiful little species is found throughout arctic America, is not uncommon in Labrador, and also occurs upon the loftier summits of the Rocky Mountains in Colorado and elsewhere. It is, as most species of the genus, essentially arctic in its habits.