284 LEPIDOPTERA. 



head and whole dorsal surface remain at this time of a dull 

 ])urple-brown, the undersurface changing to green mixed 

 with purple-brown. Thus it suits itself to either food-plant, 

 so that its deceptive resemblances are wonderfully perfect. 



August till May or June, on birch and alder ; occasionally 

 also on hazel, beech, and broom ; usually resting upon the 

 apical portion of a twig, where its extraordinary series of 

 resemblances to twigs, buds, and wrinkled opening leaves,, 

 or when half grown to a catkin, are of the most service. 

 It is best collected by searching the food-plant, since its hold 

 to the twig, by its powerful anal prolegs, is so tenacious that 

 it can scarcely be beaten off without serious risk of injury. 



Plta delicate and thin-skinned ; head portion rather 

 sharpened ; limb-covers very closely compacted, indicated by 

 thin lines ; antenna-cases broadh^ sculptured, or rather 

 wrinkled, into transverse furrows; wing-covers and back of 

 the head-piece very rugose and minutely furrowed all over ; 

 segments minutely roughened, hardly pitted, and even the 

 hind bands of the segments dull ; anal segments rounded 

 above, rather flattened below, with the anal structure con- 

 spicuous ; cremaster conical, furnished with stiff projecting 

 hooked bristles which cling closely together and hold firmly 

 to the silken cocoon, colour pale green, the wing-covers 

 tinged with brown, and the dorsal region spotted with 

 reddish-ochreous. In a slight cocoon among fallen leaves,, 

 or moss, upon the ground. 



The moth hides during the day in a birch or alder tree, or 

 among thick undergrowth, or sometimes will sit with out- 

 spread wings upon a large bramble leaf, when the harmony 

 of its colour and markings with those of the leaf is extra- 

 ordinary and most deceptive. It flies naturally at about 

 11 P.M. and later, and towards midnight is much attracted 

 by a strong (light, around which it dashes in a vigorous and 

 startling manner. 



Very generally distributed in woods, especially those iu 



