Part 27 (1/2)

(The White Admirals)

_b.u.t.terfly._--Head large; the eyes are large, naked; the antennae are moderately long, with a distinct club; the palpi are compact, stout, produced, densely scaled. The fore wings are subtriangular, the apex well rounded, the lower two thirds of the outer margin slightly excavated. The first two subcostal nervules arise before the end of the cell. The hind wings are rounded, crenulate.

_Egg._--Nearly spherical, with the surface pitted with large hexagonal cells (see p. 3, Fig. 1).

_Caterpillar._--The caterpillar in its mature state is cylindrical, somewhat thicker before than behind, with the second segment adorned with two prominent rugose club-shaped tubercles. The fifth segment, and the ninth and tenth segments also, are ornamented with dorsal prominences (see p. 8, Fig. 20).

[Ill.u.s.tration FIG. 106.--Neuration of the genus _Basilarchia_.]

_Chrysalis._--The chrysalis is suspended by a stout cremaster; the abdominal segments are rounded. On the middle of the dorsum is a prominent projecting boss. The thorax is rounded. The head is rounded or slightly bifid.

The caterpillars feed upon the leaves of various species of oak, birch, willow, and linden. The eggs are laid upon the extreme tip of the leaves, and the infant caterpillar, feeding upon the leaf in immediate proximity to the point where it has been hatched, attaches bits of bitten leaf by strands of silk to the midrib, thus stiffening its perch and preventing its curling as the rib dries. Out of bits of leaves thus detached it constructs a packet of material, which it moves forward along the midrib until it has completed its second moult. By this time winter begins to come on, and it cuts away for itself the material of the leaf on either side of the rib, from the tip toward the base, glues the rib of the leaf to the stem by means of silk, draws together the edges of the remaining portions of the leaf, and constructs a tube-like hibernaculum, or winter quarters, exactly fitting the body, in which it pa.s.ses the winter.

[Ill.u.s.tration FIG. 107.--Leaf cut away at end by caterpillar of _Basilarchia_ (Riley).]

[Ill.u.s.tration FIG. 108.--Hibernaculum, or winter quarters, of larva of _Basilarchia_.]

There are a number of species of the genus found in the United States, the habits of which have been carefully studied, and they are among our most interesting b.u.t.terflies, several species being mimics of protected species.

(1) =Basilarchia astyanax=, Fabricius, Plate XXII, Fig. 1, ?; Plate III, Figs. 17, 21, 25, larva; Plate IV, Figs. 12, 13, _chrysalis_ (The Red-spotted Purple).

_b.u.t.terfly._--This common but most beautiful species is sufficiently characterized by the plate so far as the upper surface is concerned. On the under side the wings are brownish, banded with black on the margins; the lunules are on this side as above, but the inner band of spots is red. There are two red spots at the base of the fore wings, and four at the base of the hind wings. The palpi are white below, and the abdomen is marked with a lateral white line on each side. Expanse, 3.00-3.25 inches.

_Egg._--The egg, which resembles somewhat closely that of _B. disippus_ (see p. 3, Fig. 1), is yellowish-green, gradually turning dark brown as the time for the emergence of the caterpillar approaches.

_Caterpillar._--The caterpillar is so well delineated in Plate III, Fig. 17, as to obviate the necessity for a lengthy verbal description.

_Chrysalis._--What has been said of the caterpillar is also true of the chrysalis (see Plate IV).

The larva feeds upon the willow, cherry, apple, linden (_Tilia_), huckleberry, currant, and other allied shrubs and trees. The b.u.t.terfly is somewhat variable, and a number of varietal forms have been described. It ranges generally over the United States and southern Canada as far as the Rocky Mountain ranges in the West, and is even said to occur at high elevations in Mexico.

(2) =Basilarchia arthemis=, Drury, Plate XXII, Fig. 4, ?, form =lamina=, Fabricius; Fig. 5, ?, form =proserpina=, Edwards, Plate III, Fig. 26, _larva_; Plate IV, Figs. 14, 23, _chrysalis_ (The Banded Purple).

_b.u.t.terfly._--Easily distinguished in the form _lamina_ from _astyanax_, which in other respects it somewhat closely resembles, by the broad white bands crossing both the fore wings and the hind wings, and followed on the secondaries by a submarginal row of red spots shading inwardly into blue. In the form _proserpina_ there is a tendency on the part of the white bands to become obsolete, and in some specimens they do entirely disappear. The likeness to _astyanax_ in such cases is striking, and the main point by which the forms may then be discriminated is the persistence of the red spots on the upper side of the secondaries; but even these frequently are obsolete. Expanse, 2.50 inches.

_Egg._--The egg is grayish-green, with ”kite-shaped” cells.

_Caterpillar._--Greenish-or olive-brown, blotched with white in its mature form, which is well represented in Plate III. It feeds upon the willow, the hawthorn (_Crataegus_), and probably other plants.

_Chrysalis._--The figure in Plate IV is sufficiently exact to obviate the necessity for further description.

This beautiful insect ranges through northern New England and New York, Quebec, Ontario, and the watershed of the Great Lakes, spreading southward at suitable elevations into Pennsylvania. I have taken it about Cresson, Pennsylvania, at an elevation of twenty-five hundred feet above sea-level. It is not uncommon about Meadville, Pennsylvania. The species appears to be, like all the others of the genus, somewhat unstable and plastic, or else hybridization is very frequent in this genus. Probably all the species have arisen from a common stock.

+--------------------------------------------------------------+ || | EXPLANATION OF PLATE XXII | | | | 1. _Basilarchia astyanax_, Fabricius, ?. | | 2. _Heterochroa californica_, Butler, ?. | | 3. _Basilarchia lorquini_, Boisduval, ?. | | 4. _Basilarchia arthemis_, Drury, ?. | | 5. _Basilarchia arthemis_, Drury, var. | | _proserpina_, Edwards, ?. | | 6. _Basilarchia weidemeyeri_, Edwards, ?. | | | | [Ill.u.s.tration PLATE XXII.] | +--------------------------------------------------------------+

(3) =Basilarchia weidemeyeri=, Edwards, Plate XXII, Fig. 6, ?

(Weidemeyer's Admiral).

_b.u.t.terfly._--Superficially like _arthemis_, but easily distinguished by the absence of the lunulate marginal bands of blue on the margins of the hind wings and by the presence of a submarginal series of white spots on both wings. Expanse, 3.00 inches.