THE DECEMBER MOTH. 113 



and sloe, and it is said also on birch, oak, sallow, apple, 

 bramble, etc. Those that I have found resting by day on 

 shoots of hawthorn, apparently enjoying the sunshine, have 

 almost invariably been " ichneumoned " ; but others that 

 came up after sunset to feed on the shoots were generally 

 healthy. Usually the caterpillar feeds up and pupates the 

 same year, but on the moors in Aberdeenshire and some other 

 parts of Scotland it is said to hibernate and to complete its life 

 cycle the following summer and autumn. Furthermore, the 

 moths from these winter larvae are much darker than normal, 

 and have been doubtfully referred to var. aricB^ Hiibn., a form 

 found in the Alps, Scandinavia, and Finland. 



The moth is out in August and September, and occurs in 

 wooded districts throughout the southern half of England, but 

 northwards from the Midlands it is uncommon ; it is found in 

 several parts of Scotland to Inverness. In Ireland it is reported 

 (Birchall) to have occurred in Killarney, and Kane mentions 

 that " a blackish form was taken at Magilligan, near Derry, by 

 W. Salvage. Its larvae were feeding on blackthorn." The range 

 abroad extends through Europe to Armenia and Asia Minor. 



The December Moth {P<xcilocampa populi). 



This is a rather thinly scaled moth ; the general coloration is 

 sooty brown ; the wings are suffused more or less with greyish ; 

 there are two pale ochreous cross lines on the fore wings, the 

 first enclosing a reddish brown basal patch ; hind wings rather 

 paler with a diffuse whitish central band ; fringes brown 

 chequered with pale ochreous. Head brown, collar brownish, 

 tipped with pale ochreous in the male. The female is rather 

 larger than the male. The moth is figured on Plate 50, and 

 the eggs and caterpillar on Plate 53. 



The eggs, which are laid on the bark of trees, are whitish 

 grey, variegated or mottled with darker grey. 



I 



