The Dark Crimson Underwing (Catocala sponsa).
The fore wings of this species vary in general colour from ashy grey to an almost olive brown; the dark clouding is much in evidence in some specimens, but absent in others; the white or yellow marks in the vicinity of the white outlined reniform are noticeable features. Hind wings, crimson, more or less tinged with purple; the upper half of the central black band is acutely angled on its outer edge, and bluntly so on its inner edge, thence curved to the inner margin. (Plate [32], Fig. 1.)
The caterpillar is greyish-brown with a greenish tinge, and dusted with black; paler on the fourth ring and between rings 7 and 8, and 10 and 11; the hump on ring 8 has an ochreous tip; raised spots, red, bearing black bristles; head, pale brown, (Fenn.) It feeds on oak in May and June.
The chrysalis is reddish, dusted with purplish grey, enclosed in a rather open silken cocoon between leaves. (Plate [33], Fig. 1 larva, 1a pupa.) The moth is out in July and August. Its chief home is the New Forest, Hants, where it abounds, in some years, and in others is so scarce that few specimens can be found. It has been taken occasionally in one or other of the southern English counties adjoining Hants, and has been noted in Oxfordshire and Suffolk; but such occurrences seem to be exceptional.
The Light Crimson Underwing (Catocala promissa).
Generally smaller, and the fore wings are usually greyer, than the last species; the first black cross line is inwardly shaded with blackish; on the hind wings the central black band is straighter, and the upper half, although sometimes slightly expanded, is not angled; in some examples the band does not quite reach the inner margin, and such specimens have been referred to ab. mneste, Hübner. (Plate [32], Fig. 2.)
The caterpillar is of a greenish-tinged greyish coloration, freckled with darker grey, and with yellowish brown patches on rings 4, 8, and 9. It feeds, at night, on oak, boring into the buds at first, but afterwards attacking the foliage: May and June. The moth occurs in oak woods in July and August, but it does not seem to be met with anywhere in England so frequently as in the New Forest, Hampshire. Even in that favourite locality it is seen but rarely in some seasons. It is, or has been, found in several other southern and eastern counties, but, as a rule, only in a casual way.