The general colour of this species (Plate 53, Figs. 1, 2) is whitish, more or less powdered or suffused with grey; all the {140} wings have two blackish dotted cross lines and a greyish, sometimes reddish, central shade; not infrequently there is an interrupted grey or dark greyish band on the outer marginal area, and this margin itself is always dotted with black; the rings enclosing white dots on all the wings are usually black, but sometimes reddish. In some specimens having a reddish central shade, the general colour, especially of the fore wings, is delicately tinged with reddish. Var. _subroseata_, Woodforde (Fig. 3), a form of this species occurring in N. Staffs. is slaty grey, with the space between the inner and outer cross lines of fore wings rosy pink or reddish. The caterpillar is of a green colour with slender yellowish lines along the back and sides; between the rings the colour inclines to yellowish, and the head, legs, and prolegs are reddish brown. In another form the general colour is greyish, inclining to reddish, and the lines paler grey. It feeds on birch in June and July, and again in August and September. It is said to eat alder and oak. The chrysalis, which is similar in shape to that of the last species (Plate 51), is pale greyish-ochreous marked with dark brown. The moth, which appears in May and June, and in some seasons in August, frequents woodlands and heaths where birch flourishes. Although fairly plentiful in most of the southern English counties, it appears to be rare in Dorset and Devon, and more or less so in the eastern counties. It is very local in Nottinghamshire and Yorkshire, but not uncommon at Strensall in the latter county; and although it has been recorded from Cumberland, it seems to be absent from Lancashire and Cheshire. Doubtfully reported from North Northumberland, but found in Wells Wood, Roxburghshire, and appears to be widely distributed in Scotland, although generally scarce in that country. In Ireland it is local, but not uncommon sometimes. The range abroad extends to Eastern Siberia. [Illustration] 2 Pl. 52. 1. MALLOW: _caterpillar_. 2. SHADED BROAD-BAR: _caterpillar_. 3. CHALK CARPET: _caterpillar_. [Illustration] 2 Pl. 53. 1, 2, 3. BIRCH MOCHA. 4, 5. DINGY MOCHA. 6, 9. THE MOCHA. 7, 8. FALSE MOCHA. 10-12. MAIDEN'S BLUSH. 13, 14. CLAY TRIPLE-LINES. {141} HYDRIOMENINAE. THE VESTAL (_Sterrha sacraria_). The fore wings are pale yellow inclining to ochreous, and the front edge is more or less tinged with the same colour as that of the oblique stripe from the tips of the wings to the middle of the inner margin. In the type, this stripe is purplish-brown, but in ab. _labda_, Cramer, it is crimson, and in ab. _atrifasciaria_, Stefan, it is blackish. In ab. _sanguinaria_, Esper, the ground colour is pinkish. The hind wings are always white. (Plate 54, Figs. 1 and 2.)