The Butterfly Book Part 61

_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, ? (Alpheus).

_b.u.t.terfly._--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)

_b.u.t.terfly._--The antennae have a moderately large club, curved, bluntly pointed. The palpi are porrect, the third joint almost concealed in the dense hairy vest.i.ture 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 b.u.t.terflies comprised in this genus are all, without exception, dark in color, in a few species having bright spots upon the hind wings.

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

[Ill.u.s.tration FIG. 160.--Neuration of the genus _Thanaos_.]

_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).

_b.u.t.terfly._--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 lat.i.tude of New England to that of Arizona.

(2) =Thanaos icelus=, Lintner, Plate XLVIII, Fig. 17, ?; Plate VI, Fig.

27, _chrysalis_ (The Dreamy Dusky-wing).

_b.u.t.terfly._--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, ? (The Dark Dusky-wing).

_b.u.t.terfly._--A little larger than the preceding species, especially in the female s.e.x. 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).

_b.u.t.terfly._--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_).

_Lucilius_ ranges from New England to Georgia, is common in western Pennsylvania and West Virginia, and extends westward at least as far as the Rocky Mountains.

(5) =Thanaos persius=, Scudder, Plate XLVIII, Fig. 1, ?; Plate VI, Fig.

34, _chrysalis_ (Persius' Dusky-wing).

_b.u.t.terfly._--This is a very variable species, some specimens being light and others dark in color. There is scarcely any positive clue to the specific ident.i.ty of the insect except that which is derived from the study of the genital armature of the male, which is a microscopic research capable of being performed only by an expert in such matters.

The student may be pardoned if, in attempting to cla.s.sify the species of this genus, and the present species in particular, he should grow weary, and quote a few biblical expressions relating to Beelzebub, the "G.o.d of flies." Expanse, 1.20-1.45 inch.

_Early Stages._--The caterpillar feeds on willows. Scudder has with patient care described its life-history.

The insect ranges from New England southward, and inland across the continent to the Pacific.

(6) =Thanaos afranius=, Lintner, Plate XLV, Fig. 5, ? (Afranius'

Dusky-wing).

_b.u.t.terfly._--Closely related to the preceding species. The hind wings on the upper side in the male s.e.x are almost solid black, the fringes paler. On the under side there is a double row of light spots along the margin of the hind wing in both s.e.xes. The female is generally paler in color on the upper side than the male.

_Early Stages._--Unknown.

All the specimens I have seen come from Arizona, where the thing is apparently common.

(7) =Thanaos martialis=, Scudder, Plate XLVIII, Fig. 4, ?; Plate VI, Fig.

37, _chrysalis_ (Martial's Dusky-wing).

_b.u.t.terfly._--The upper side of the wings is paler than in most species, and has a distinctly purplish-gray cast. The fore wings are crossed by irregular bands of dark spots. The hind wings on the outer half are profusely mottled with small pale spots. All the light spots are repeated on the under side of both wings, and are more distinct on this side than on the upper. Expanse, 1.25-1.40 inch.

_Early Stages._--These are partly known. The caterpillar feeds on _Indigofera_ and _Amarantus_.

The species ranges from Ma.s.sachusetts to Georgia, and westward to Missouri and New Mexico.

(8) =Thanaos juvenalis=, Fabricius, Plate XLVIII, Fig. 11, ?; Plate VI, Fig. 33, _chrysalis_ (Juvenal's Dusky-wing).

_b.u.t.terfly._--Larger than the preceding species. The wings have a number of translucent spots arranged as a transverse series beyond the middle of the wing. They are far more distinct and larger in the female than in the male. The under side of the wings is paler than the upper side, and profusely but indistinctly marked with light spots. Expanse, 1.35-1.60 inch.