LIPARID^. 



301 



feeds. Ou coming out in April from liybernatiou, they are 

 30 small as to appear as though but just hatched, and are 

 very dull and dingy in appearance. A fresh silken covering 

 is prepared for each change of skin up to the fourth. The 

 larv£e feed mainly at night, hiding by day in chinks of bark, 

 more especially on the underside of branches, where, when 

 well grown, they are easily seen. 



Pupa glossy black, with abundant tufts of white hairs 

 arranged in sis rows on the back and sides, four of the rows 

 commencing from the head. In a thin silken cocoon 

 between leaves, or in the angles of the bark of the trunk, or 

 branch, of the tree on which the larva has fed, or in any 

 suitable corner. 



The moth sits by day on the trunks and branches of 

 poplar and willow trees, or on fences, and is quite con- 

 spicuous and extremely sluggish. At night it flies actively, 

 comes freely to light, and has even been seen upon the sugar 

 used to attract Noctuse. 



It is extraordinarily and perplexingly irregular in numbers, 

 appearing in favourite places, such as the Isle of Shepj)ey, in 

 certain years, in such multitudes that the poplars are stripped 

 of their leaves, and the moths in the evening almost remind 

 an observer of a snow-storm. In other years but few are 

 seen. These fluctuations are the more difiicult to explain 

 since the larvae are most distasteful to birds, and appear to be 

 almost exempt from the attack of insect pai^asites. On the 

 Continent it is more constant in its numbers, and so injurious 

 as greatly to check the growth of the poplar and willow 

 trees, and its destruction is an important part of the duty of 

 the foresters. Formerly it was plentiful throughout our 

 Southern counties, including the outskirts of London, where 

 its beautiful larvEC were conspicuous on the undersides of the 

 branches of every poplar, while in 1857 the willow trees in 

 and around the suburbs were almost stripped of leaves. 

 More locally it was also common in the Eastern and Mid- 



