together with a few threaas of silk. It lies concealed during the day and feeds at night. A minute account of all its peculiarities is given by Scudder in "The Butterflies of New England," vol. ii, p. 1519.

The insect ranges over the whole of temperate North America. (2) Pholisora hayhursti, Edwards, Plate XLVIII, Fig. 16, (Hayhurst's Skipper).

Butterfly.—Easily distinguished from the preceding species by the somewhat crenulate shape of the outer margin of the hind wings, the white color of the under side of the abdomen, and the different arrangement of the white spots on the fore wings, as well as by the dark bands which cross both the fore and the hind wings on the upper side. Expanse, .90-1.15 inch.

Early Stages. Our information as to these is incomplete. The species ranges from the latitude of southern Pennsylvania westward and southward to the Gulf, as far as the Rocky Mountains.

(3) Pholisora libya, Scudder, Plate XLVIII, Fig. 14, ♂ (The Mohave Sooty-wing).

Butterfly.-Easily distinguished from the two preceding species by the white fringes of the wings and by the markings of the under side. The primaries on the lower side are dark, tipped at the apex with light gray, and in the female having the costa and the outer margin broadly edged with light gray. The hind wings are pale gray of varying shades, marked with a number of large circular white spots on the disk and a marginal series of small white spots. Expanse, 8, .80-1.25 inch; 9, 1.15-1.40 inch.

Early Stages.-These await full description.

This species is found from Nevada to Arizona, and is apparently very common in the Mohave Desert.

(4) Pholisora alpheus, Edwards, Plate XLV, Fig. 2, 3 (Alpheus).

Butterfly. This little species is nearer P. hayhursti than any of the others we have described, but may at once be recognized and discriminated by the checkered margins and white tip of the fore wing and the linear shape of the spots composing the submarginal and median bands on the upper side of this wing. The hind wings on the under side are marked with a number of light spots arranged in marginal and median bands.

Early Stages.-Unknown.

Alpheus occurs in Nevada, Arizona, and New Mexico.
There are four other species of the genus found in our fauna.

Genus THANAOS, Boisduval

(The Dusky-wings)

Butterfly. The antennæ have a moderately large club, curved, bluntly pointed. The palpi are porrect, the third joint almost concealed in the dense hairy vestiture of the second joint. The neuration of the wings is represented in the cut. The fore wing in the case of the male always has a costal fold. The butterflies comprised in this genus are all, without exception, dark in color, in a few species having bright spots upon the hind wings.

FIG. 160.

Neuration of the genus Thanaos.

The genus reaches its largest development in North America. The discrimination of the various species is somewhat difficult.

Egg.-The egg is somewhat like the egg in the genus Achalarus, but the micropyle at the upper end of the egg is relatively larger and not as deeply depressed below the surface. The sides are ornamented, as in Achalarus, by raised vertical ridges, between which are numerous cross-ridges; in a few cases the vertical ridges are beaded, or marked by a series of minute globose prominences, upon the edge.

Caterpillar.-The caterpillars are cylindrical, tapering from the middle forward and backward, marked with lateral and dorsal stripes, with the neck less strangulated than in the preceding genera.

Chrysalis. Not greatly differing in outline from the chrysalis of the preceding genera, in most species having the outline of the dorsum straight on the abdominal segments, with the thoracic segments forming a slight hump or elevation; convex on the ventral side, the cremaster being usually well developed.

(1) Thanaos brizo, Boisduval and Leconte, Plate XLV, Fig. 7, ; Plate VI, Fig. 38, chrysalis (The Sleepy Dusky-wing).

Butterfly.-The band of postmedian spots on the fore wing is composed of annular dark markings, is regular, crosses the wing from the costa to the hind margin, and is reproduced on

the under side as a series of pale-yellowish spots more or less distinct. The hind wings have a double series of faint yellow spots; these as well as the marginal spots of the primaries are very distinct on the under side. Expanse, 1.25-1.60 inch.

Early Stages.-The caterpillar feeds on oaks, Galactia, and possibly Baptisia. The life-history has been only partially ascertained, in spite of the fact that the insect has a wide range and is

not uncommon.

Brizo occurs from the Atlantic to the Pacific, ranging from the latitude of New England to that of Arizona.

(2) Thanaos icelus, Lintner, Plate XLVIII, Fig. 17, ; Plate VI, Fig. 27, chrysalis (The Dreamy Dusky-wing).

Butterfly. Prevalently smaller in size than the preceding species. The under side of the wings is paler than the upper side, and the outer third of both the primaries and secondaries is marked with a profusion of small indistinct yellow spots, which do not form well-defined bands as in the preceding species. On the upper side of the fore wing the median area is generally marked by a broad band of pale gray, but this is not invariably the case. Expanse, 1.00-1.20 inch.

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, 3 (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, 8, 1.25 inch; 9, 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, 8; Plate VI, Figs. 30-32, chrysalis (Lucilius' Dusky-wing).