BOMBYCID^. n 



together, or even crawl one upon another, on the surface of the 

 web, in fine weather basking in the sunshine ; or crowd within 

 it, when the weather is cold or wet, and show the utmost 

 sociability of disposition. After the last moult they scatter 

 and become quite solitary, wandering sometimes to a con- 

 siderable distance before spinning up. If kept in confine- 

 ment and not allowed plenty of air and sunshine they become, 

 at this stage, excessively restless, and refuse to spin up, con- 

 tinuing to feed a little and wandering about, sometimes, until 

 far into the autumn, after which most of them die. On the 

 Continent, where the insect is more generally abundant, it 

 feeds in addition on cherry, plum, lime, sallow, and birch. 



Pupa short and thick, rather broad ; dark brown. In a 

 small firm egg-shaped cocoon, very small for the size of the 

 larva, and composed of silk mixed with a peculiar pasty 

 material, which is secreted by the larva, and when dry has a 

 somewhat chalky, dusty appearance. This substance, mixed 

 with the silk, forms the outer surface of the cocoon, and is 

 pierced with a number of minute holes, probably for the passage 

 of air, but inside there is a silken lining which shows no trace 

 of these breathing pores. When the moth emerges a lid is 

 pushed off at one end of the cocoon, having been to all 

 appearance carefully cut partially through, from the inside, by 

 the pupa, for this purpose. The pupa of this species has 

 other strange peculiarities. Its time for production of the 

 moth is quite problematical. Very few emerge in the spring 

 following the change to pupa, many more, apparently, in the 

 second and third years, others still later, up to seven, or it is 

 even said to nine years after pupation. Yet if the cocoon is 

 cut open and the pupa examined the moth is usually to be 

 found fully formed therein, and an individual so liberated has 

 even been known to spread its wings and assume in all respects 

 the appearance of a moth which had emerged of its own accord 

 Moreover, the production of the moths may be stimulated, 

 and that without any excessive delay, since I have myself, in 



