There are two distinct colour forms, one is greyish white (ab. _spoliata_, Staudinger), and the other decidedly ochreous; the former is sometimes tinged with ochreous, and sometimes heavily sprinkled with dark grey. In the type form of _aversata_, the general colour is greyish white, and the space between the central and outer lines of the fore wings, and that enclosed by the first and central of the hind wings, is more or less entirely filled up with dark grey inclining to blackish; occasionally the dark colour spreads beyond the outer line, and covers a large portion of the outer area. These bands also occur in the ochreous and intermediate colour forms. A specimen, bred in June by Mr. W. G. Sheldon, from a caterpillar found on a fence at West Wickham in May, had the wings and abdomen black, but the head, thorax, anal tuft, and fringes of the wings were normal. (Plate 46, Figs. 3-6.) The caterpillar (Plate 47, Fig. 2; from coloured drawing by Mr. Sich) is much wrinkled, rather thickened behind, and tapers gradually towards the small, black-flecked head; the general colour is brownish, merging into ochreous on the hinder rings; a darker brown shade along the back, interrupted on the middle rings by V-shaped marks, encloses a slender whitish line, and there is a whitish spot on ring eight; a wavy pale ochreous line low down along the sides. (Adapted from Fenn.) It feeds on dandelion, dock, primrose, bedstraw, knotgrass, and many other low-growing plants; after hibernation, from April to May, it will thrive on the young growth of sallow, birch, hawthorn, etc. It will sometimes feed up and reach the moth state in August or September. The moth flies in June and July, and is generally distributed; but in Scotland does not seem to have been observed north of Moray. {121} SMALL FAN-FOOTED WAVE (_Acidalia_ (_Ptychopoda_) _bisetata_). One form (Plate 46, Fig. 10) has whitish wings, with a deep, dark-grey border on the outer area of all the wings; this border is traversed by a whitish, wavy line (ab. _fimbriolata_, Stephens). Another form (Plate 46, Fig. 7) is more or less typical, and in this it will be noted that the marginal borders are much paler, and are broken up into bandlets. Between these two forms there are modifications, and sometimes a greyish shade spreads over all the wings.