Early Stages.—These have been described by Scudder. The caterpillar feeds on a variety of plants, as the aspen, oaks, and witch-hazel.
Icelus ranges across the continent from Nova Scotia to Oregon, and south to Florida and Arizona.
(3) Thanaos somnus, Lintner, Plate XLVIII, Fig. 2, ♂ (The Dark Dusky-wing).
Butterfly.—A little larger than the preceding species, especially in the female sex. The male is generally quite dark, the banding of the fore wing on the upper side obscured. The hind wings have a row of light marginal and submarginal spots, more distinct on the under side than on the upper. The female generally is light gray on the upper side of the wings, with broad median and submarginal bands of dark brown, tending to fuse or coalesce at a point near the origin of the first median nervule. Expanse, ♂, 1.25 inch; ♁, 1.50 inch.
Early Stages.—But little is known of these.
All of the specimens I have ever seen came from southern Florida.
(4) Thanaos lucilius, Lintner, Plate XLVIII, Fig. 10, ♂; Plate VI, Figs. 30-32, chrysalis (Lucilius' Dusky-wing).
Butterfly.—This species may be distinguished from T. pacuvius, a near ally, by the more mottled surface of the secondaries, which in pacuvius are almost solidly black; and from T. martialis, another close ally, by the absence of the purplish-gray cast peculiar to both sides of the wings of the latter species, and the less regular arrangement of the bands of spots on the upper side of the fore wings. The plate does not show these delicate but constant marks of difference as well as might be desired. Expanse, 1.20-1.40 inch.
Early Stages.—Dr. Scudder has fully described these. The caterpillar feeds on the columbine (Aquilegia canadensis).