This moth is usually brown in colour. The fore wings are inclined to dark reddish brown, and have a pale ochreous brown curved band or ring at the base, a slightly curved line or band of the same colour beyond the middle of the wing; central spot {120} white, finely margined in black. Except that the female is generally larger, and the cross lines usually less distinct, the sexes are much alike. This brown form occurs most frequently in Britain, but in parts of the Kentish and Sussex coast, and especially the Romney Marsh district, a yellowish form is obtained. In such specimens the cross lines are darker. In both forms one or both cross markings may be faint or quite absent, and even the white central dot, which varies in size and shape, may be missing. Sometimes the outer band is distinctly broad and outwardly diffuse (Plate 56). The eggs, which appear to be laid loosely, are pale whitish brown, roughened with darker brown, and the micropylar area is purplish brown. Some that I received on March 2, 1907, appeared to be on the point of hatching on the 5th of that month, but no larva came out, although one of the eggs was chipped at one end. It has been frequently stated that the caterpillars hatch out in the autumn and hibernate, but as has been pointed out by Tutt ("Nat. Hist. Brit. Lep.," ii. 20), the eggs of this species probably do not hatch until some time during February or March, although when kept indoors the caterpillar has emerged from the egg in January. The full-grown caterpillar is black, velvety between the rings, covered with golden brown hair on the back and greyer hair on the sides, among which are some black ones; three interrupted whitish lines on the back; some of the hairs along the middle of the back stand erect and form a ridge, looked at from either end. Head lightish brown in colour, lined with black. Feeds in the spring months and up to June chiefly on various kinds of grass. Among many of the plants that it has been known to eat are trefoils, bird's-foot (_Ornithopus_), sea thrift (_Statice_), heather, sallow, hawthorn, sloe, plum, bramble, etc. With regard to the food, it is interesting to note that although one rearer will find that sallow is excellent for the caterpillars, another considers that sallow or hawthorn are but poor {121} substitutes for kidney-vetch (_Anthyllis vulneraria_) upon which the caterpillars were feeding when found (Plate 57).