THE FROSTED GREEN. 93 



is a g-ood growth of birch, by jarring the twigs and branches of 

 birch upon which it rests during the day, or it may be found 

 by searching the low bushes and underwood. Soon after dusk 

 it is on the wing, and. will then visit sugar and sallow bloom. 



Generally distributed throughout (^reat Britain. In Ireland 

 it appears to be very rare. Its range abroad, in the typical 

 form, extends over Northern and Central Europe to North Italy 

 and to South-east Russia. 



The Frosted Green {BAyj^l^^t^ ridcns). 



This moth (Plate 39, Figs. 9, 10) is also on the wing early in 

 the year, but although it is sometimes found on tree trunks in 

 April or perhaps as late as the first week in May, it seems 

 to be rarely obtained otherwise in the perfect state. It does 

 not "come to sugar" often, if at all, and so far as is known, 

 does not visit any of the usual natural attractions. 



The ground colour of the fore wings varies from whitish to 

 green, but in some specimens the general hue is olive or blackish 

 green, and the markings then appear to be w^avy whitish lines 

 crossing the wings, one near the base, and the other before the 

 outer margin. 



The caterpillar (Plate 38, Fig. i) is yellow above and rather 

 greenish beneath ; a greenish grey double stripe along the back 

 is interrupted at the ring divisions ; there are also white dots with 

 black or blackish edges on the back and the sides ; a yellow line 

 along the spiracle area is shaded above and below with greenish 

 grey ; the head, which is notched on the crown, is yellowish, 

 with a black mark on each cheek. It feeds, at night, on oak, 

 from May to July ; hiding by day on the underside of a le.if, a 

 portion of which is folded over and secured with silk', to fonu a 

 suitable retreat. These caterpillars respond more readily to 

 the persuasive beating-stick than others of the group. 



The species affects woodland localities in most of the southern 



