_Butterfly._--Medium-sized or small butterflies, dark in color, wings marked on the under side with eye-like spots; the antennæ short, with a gradually thickened club. The eyes are naked. The costal vein of the fore wing is generally strongly swollen at the base. The subcostal vein is five-branched; the first two nervules generally emitted before the end of the cell; the third nearer the fourth than the end of the cell; the fourth and fifth nervules spring from a common stem, the fourth terminating immediately on the apex. The lower radial is frequently projected inwardly into the cell from the point where it intersects the union of the middle and lower discocellular veins. The outer margins of both wings are evenly rounded. [Illustration FIG. 118.--Neuration of the genus _Erebia_, enlarged.] _Egg._--Subconical, flattened at the base and at the top, the sides marked by numerous raised vertical ridges, which occasionally branch or intersect each other. _Caterpillar._--The head is globular, the body cylindrical, tapering gradually backward from the head, the last segment slightly bifurcate. _Chrysalis._--The chrysalis is formed about the roots of grass and on the surface of the ground, either lying loosely there or surrounded by a few strands of silk. The chrysalis is convex, both ventrally and dorsally, humped on the thorax, produced at the head; all the projections well rounded. The chrysalids are generally some shade of light brown or ashen-gray, with darker stripes and spots. This genus is arctic, and only found in the cooler regions of the North or upon elevated mountain summits. A few species range downward to lower levels in more temperate climates, but these are exceptional cases. (1) =Erebia discoidalis=, Kirby, Plate XXV, Fig. 19, ♂ (The Red-streaked Alpine). _Butterfly._--Easily distinguished by the plain black wings, relieved by a reddish-brown shade on the disk of the primaries on the upper side. _Early Stages._--Hitherto undescribed. This species is found in the far North. My specimens came from the shores of Hudson Bay. (2) =Erebia disa=, var. =mancinus=, Doubleday and Hewitson, Plate XXV, Fig. 23, ♂ (The Alaskan Alpine). _Butterfly._--The wings are dark brown on the upper side. On the outer third below the apex are three or four black ocelli, broadly ringed with red and pupiled with white. The upper ocellus is generally bipupiled, that is to say, the black spot is twinned, and there are two small light spots in it. On the under side the fore wings are as on the upper side. The hind wings are broadly sown with gray scales, giving them a hoary appearance. The base is more or less gray, and there is a broad, regularly curved mesial band of dark gray, which in some specimens is very distinct, in others more or less obsolete. The female does not differ from the male, except that the ocelli on the fore wings are larger and more conspicuous. _Early Stages._--Unknown.