BOMBYCID^. 45 



July to May on hawthorn, blackthorn, willow, buckthorn 

 and various fruit trees ; hiding upon the bark, generally low 

 down, in the day time, crawling up to feed at dusk, and 

 feeding through the night. It feeds but slowly during the 

 autumn, and, while still rather small, hybernates upon the 

 stem of its food plant. Mr. W. Holland writes: "I had some 

 trouble to point them out, so well had they disposed them- 

 selves for the winter. They placed themselves straight along 

 the twigs head downwards, spun a little silk to hold themselves 

 firm, and, being so very flat beneath, laid so close to the twig 

 as to look like a part of it. They are not easy to find even 

 when fully grown, they are so much like the twigs and lie as 

 closely along them as ever. They hide often inside a clipped 

 hawthorn hedge where it is impossible to get at them." 

 Another observer compares the young larvae to bits of 

 dead ivy stem, left clinging to the bark, the lateral protu- 

 berances imitating the pseudo-rootlets of the ivy. The well- 

 grown larva, when stretched upon the bark of a fruit tree, 

 has even been mistaken for a piece of discoloured string, 

 such as that with which the young trees are tied to their 

 supports. 



Sometimes the well -grown larvse are ornamented with 

 whitish blotches, especially on the dorsal region. Upon this 

 a most interesting experiment has been made by Professor 

 Poulton. He divided a batch of eggs of this species, and fed 

 one portion of the young larvaB on food plants of ordiuary 

 character, but the other portion on similar food, the stems of 

 which were crusted with grey lichens. The larvae of the 

 first batch grew up of the usual dark colour, only one showing 

 some indication of white blotching; but the larvae fed 

 up among the lichen-covered twigs were nearly all blotched 

 with white, many most beautifully and extensively so. To 

 produce this result, it appeared to be necessary to expose the 

 larvae to this peculiar influence when very young ; a removal 

 of those on the bare twigs, when older, to twigs covered with 

 lichen, was productive of no observable result. 



