I40 THE MOTHS OF THE BRITISH ISLES 



wings have two blackish dotted cross Hnes and a greyish, some- 

 times 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 Stren- 

 sall 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 some- 

 times. 



The range abroad extends to Eastern Siberia, 



