Genus Grapta Kirby (the Angle-wings)
Medium-sized or small butterflies; fore wing strongly acuminate at end of upper radial, deeply excavated on outer and inner border; hind wing tailed at end of third median nervule; cells on both wings closed; palpi heavily scaled beneath. Upper side of wings tawny, spotted with darker, under side mimicking the color of bark and dead leaves, often with a silvery spot about middle of hind wing. The butterflies hibernate in winter. Eggs taller than broad, tapering toward top, which is flat, adorned with a few longitudinal ribs, increasing in height upward, laid in clusters, or strung together, then looking like beads. Larva with squarish head; body cylindrical, adorned with branching spines. Chrysalids with head bifid; prominent tubercle on back of thorax; two rows of dorsal tubercles on abdomen; compressed laterally in thoracic region; color wood-brown or greenish. The caterpillars feed upon plants of the nettle tribe, including the elm and hops, though willows, azalea, and wild currants are affected by different species.
The genus is confined to the northern temperate zone. We have about a dozen species in America, of which five have been selected for illustration.
(1) Grapta interrogationis (Fabricius), form fabricii Edwards, Plate XXV, ♂ (The Question-sign).
The largest species of the genus in our fauna. Dimorphic, the upper sides of the hind wings in the form fabricii being fulvous with dark markings, those of the form umbrosa Lintner being uniformly dark, except at base. In the Middle States double-brooded. The second brood hibernates in the winged form. Expanse 2.50 inches.
Found throughout Canada and the United States, except on the Pacific Coast.
(2) Grapta comma (Harris), form dryas Edwards, Plate XXVI, ♂ (The Comma Butterfly).
Larvæ feed on nettles; some are almost snow-white. The species is dimorphic. In the form dryas Edwards the hind wings are dark above, in the form harrisi Edwards they are lighter in color. Expanse 1.75-2.00 inches.
The range is much the same as that of the Question-mark.
(3) Grapta faunus Edwards, Plate XXVII, ♀ (The Faun).
Readily recognized by the deep indentations of the hind wings, the heavy black border, and the dark tints of the under side mottled conspicuously with paler shades. Expanse 2.00-2.15 inches. The larva feeds on willows.
Ranges from New England and Ontario to the Carolinas, thence westward to the Pacific.
As I have remarked of the genus Argynnis that it is difficult, so also I may say of the genus Grapta that it provokes much discussion among those who have not had the opportunity to study full series of specimens of the various species. The resemblances are very great, and the differences are not accentuated, so that the superficial observer is easily led astray. The differences are, however, valid, even on the upper side of the specimens, which are more nearly alike than the lower side. Take the two species here presented to view on opposite pages. They resemble each other closely, but the student will soon see that there are differences, and these are constant. On the under side they are very great, G. faunus being light in color below, while G. silenus is very dark. In both species at the end of the cell of the hind wing there is on the under side a silvery spot which has the form of an inverted L (⅂), or is rudely comma-shaped.
(4) Grapta silenus Edwards, Plate XXVIII, ♂, Type (The Toper).
Wings in form very much like those of G. faunus, but the fore wing not as strongly produced at the ends of the upper radial, and the hind wing at the end of the first submedian. The wings are much darker below than in faunus, without large pale spots, at most sprinkled with white scales. Expanse 2.00-2.30 inches.
Occurs in British Columbia, Washington, and Oregon.
The life history of this species is not as yet known. It is highly probable that the insect has the same tastes as the other species of the genus, and lives upon much the same food-plants. The late W. G. Wright, who was a careful observer, states that the butterfly haunts partially wooded places upon hillsides in the region where it is found. It is to be hoped that some bright young person in Oregon or Washington may succeed in breeding the larvæ to maturity, giving us an account of his observations. It is a mistake to suppose that everything which is worth knowing is already known about our lepidoptera. There is much for the students of the future to find out.
(5) Grapta progne (Cramer), Plate XXIX, ♂ (The Currant Angle-wing).
Somewhat smaller than any of the foregoing species. Fore wings light fulvous shading into yellow outwardly. The dark markings are smaller than in the other species, but pronounced and clearly defined. Wings below very dark, sprinkled with lighter scales. Expanse 1.85-2.00 inches.
The larva feeds upon all kinds of plants belonging to the currant family.
Ranges from Siberia to Nova Scotia, thence south to the latitude of Pennsylvania.