Common Carpet (Xanthorhoë (Epirrhoë) sociata).
The white ground colour of this species is nearly always obscured, to a greater or lesser extent, by greyish markings and suffusions on the basal area; the outer margin is broadly bordered with dark grey, and the white band between this and the dark-grey central band is intersected throughout its length by a grey line. As shown on Plate [81], Figs. 6, 7, the central band varies in width; it is often contracted below the middle, sometimes completely severed at this point, and in ab. degenerata,
Haworth, both portions are much reduced in width. Figs. 8 and 9 represent two specimens from the Isle of Lewis; these brownish-grey examples are var. obscurata, South. There are intermediate modifications leading up to a form in which the whole of the central third of the fore wings is whitish, with the usual cross lines dingy grey, and some tiny clouds of the same colour around the black discal spot.
The caterpillar is very like that of the last species referred to, but it is rather smaller in size and rougher in appearance. There is variation in the general colour, from pale fawn through greenish-brown, to dull or bright green, and sometimes the markings are tinged with reddish (Hellins).
It feeds on bedstraw, in June and July, and a second brood occurs in September. The figure of the brownish, inclining to reddish, chrysalis (Plate [79], Fig. 4), is from a photo by Mr. H. Main, and is twice the natural size.
The moth is out in May and June, and, in the South especially, again in August and September. It is generally distributed over the British Islands, but so far has not been noted from the Shetlands.
The range abroad extends to Eastern Siberia and Amurland.
According to Prout, the earliest name for this species is alternata (Müller).
Small Argent and Sable (Xanthorhoë (Epirrhoë) tristata).
On Plate [81] are shown three examples of this variable species. Fig. 10 represents the typical form from N. Devon. Fig. 11 is a black-marked specimen from Yorkshire, and Fig. 12 depicts a smoky-brown marked specimen from Clydesdale, in which the ground colour has a brownish tinge. All these have the central band more or less entire, but this character may be broader or narrower, and is sometimes divided into two parts, and these reduced to very small proportions; the white projections into