Genus ŒNEIS, Hübner
(Chionobas, Boisd.)
(The Arctics)
"To reside In thrilling region of thick-ribbed ice."
Shakespeare.
Butterfly.—The antennæ are short; the eyes of moderate size; the front full, protuberant; the palpi slender; the fore wings somewhat produced at the tip, with the outer margins rounded and the hind margins very slightly, if at all, sinuated. The nervules of the fore wings are slightly dilated toward the base; the hind wings are elongated, oval, with the outer margins evenly rounded. The color of these butterflies is some shade of brown; the outer margin is generally lighter than the base of the wing, and is marked with black spots, sometimes pupiled with white. The wings are generally marbled and mottled on the underside, and sometimes crossed on the middle of the hind wings by a broad band of darker color. The fringes are brown, checkered with white.
[a]Fig. 122.]—Neuration of the genus Œneis, enlarged.
Egg.—The egg is ovate-spherical, higher than broad, marked on the side from the apex to the base with raised sculptured ridges. These eggs are deposited, so far as we have been able to learn, on dried grass and the stems of plants in proximity to the growing plants upon which the young caterpillars are destined to feed.
Caterpillar.—The head of the caterpillar when it emerges from the egg is somewhat larger than the rest of the body, but as it passes successive moults and attains maturity the relative thickness of the body increases, and the adult larva tapers a little from about the middle in either direction. The larvæ are pale green or brown, marked by darker stripes upon the back and on the sides, the markings on the sides being in most species more conspicuous than those on the back. The species all feed on grasses.
Chrysalis.—The chrysalids are stout, very slightly angulated, and are formed, so far as we know, unattached, under stones and at the roots of grasses. When pupating, the caterpillar often makes for itself a slight depression or cell in the soil, in which a few threads of silk have been deposited, though not enough to justify us in calling the structure a cocoon.
This genus is composed of butterflies which are mainly arctic in their habitat, or dwell upon the summits of lofty mountains, where the summer is but brief. Only a few species are found at comparatively low elevations, and these in British America, or the parts of the United States immediately contiguous to the Canadian line. The most widely known of all the species up to this time is the White Mountain Butterfly, Œneis semidea, Say, a colony of which has existed probably ever since the glacial period upon the loftiest summit of Mount Washington, in New Hampshire. A number of species are found in the region of the Rocky Mountains. One species, Œneis jutta, Hübner, occurs in Maine, Nova Scotia, and parts adjacent. There are in all about a score of species of this genus recognized by authors as occurring in our fauna. In spite of the fact that these insects are boreal or arctic in their habits, Mr. W.H. Edwards has with marvelous skill and patience succeeded in obtaining the eggs and rearing at his home in Coalburg, West Virginia, a number of species. We are indebted to him for more of our knowledge of the generic characteristics of these insects, in their early stages, than had been ascertained hitherto during a century of investigation. His work is one of the beautiful triumphs of that enduring zeal which is a supreme quality in the naturalist. In their early stages all of the species show a close likeness to one another.