In its typical form (Plate [103], Fig. 10), the fore wings are whitish ochreous with the veins showing up white more or less clearly. A form with reddish ochreous fore wings has been named var. ochracea, Tutt; and another with silvery-white wings var. argentea by the same author. These seem to be identical with forms of this species named flavida and albida by Aurivillius some eight years earlier.
The hairy caterpillar is blackish or dark grey brown freckled with black; two stripes along the back and one on each side are yellow, sometimes marked with orange; the warts are orange with pale, and a few black, hairs; head black, marked with yellowish.
It feeds from July to September on the leaves of reeds, at night; hiding by day under leaves low down. The moth is out in June, but an autumn brood is sometimes obtained. It only occurs in fenland, chiefly Norfolk and Cambridgeshire.
The Marbled Beauty (Bryophila perla).
Typically the fore wings of this species are white, marbled with slaty grey, and with the stigmata dark grey (Plate [103], Figs. 9♂, 12♀). There is less colour variation than in the last species, but in some localities greenish, ochreous, and ochreous brown forms have been obtained. The caterpillar is pale slaty grey, with an irregular yellowish stripe on the back, with black spots forming a central line; the raised spots are black and shiny, as also is the head. Feeds on lichens growing on old walls from August to May. The moth, which occurs throughout England, Wales, Ireland, and Scotland up to the Clyde, is to be found, commonly as a rule, on walls by day, and gas lamps at night, in July and August. Sometimes I have found specimens on tree trunks.
Marbled Green (Bryophila muralis (glandifera)).
Two forms of this very variable little moth are represented on Plate [103], Figs. 8♂ (typical), 11♀. The ground colour of the fore wings ranges from almost white through pale green to bluish green or to a deep olive green, or through pale ochreous to orange brown. The markings, too, vary in intensity, and are sometimes very obscure. Several forms have been named, but only the Cambridge race, known as var. impar, Warren, can here be referred to. In this form the colour is more often greyish or brownish white, than green; the markings are cloudy and not clearly defined.
The caterpillar is obscure greenish, with whitish and rather
shining raised spots; there is a black plate on the first ring, and from this three broken yellowish lines run along the back. Head black and glossy. It feeds from October to May on the lichens growing on walls and rocks; during the day it hides in a chamber formed of silk and lichen, which is not easy to detect in dry weather. The moth is out in July and August, and at Eastbourne I have found it in September. It may be found generally on walls, but sometimes on rocks at various places on the coast of Kent, Sussex, Dorset, Devon, and Cornwall; also in the Scilly Isles. Its range, according to Barrett, extends to Bath and Wells, Somersetshire, Marlborough and Chippenham in Wiltshire, and it has also occurred in Gloucestershire.