CH. HI.] INSECTS WHICH FORM COCOONS. 53 



they are termed in some parts of the country, wool- 

 ly-bears. Some of these, on their changing to the 

 chrysalis state, cast off their skin at once with the 

 hair still attached to it, as may be seen from the 

 exuviae contained in the cocoon; but many, pre- 

 vious to becoming pupae, strip themselves of their 

 coat of hairs, which they incorporate with the silk 

 of their cocoons. Among these, the processionary 

 caterpillars, of which we have given an account in 

 our previous volume, may be mentioned. This in- 

 teresting insect (the Cnethocampa processionea), was 

 introduced by Martin and Stewart, as a British spe- 

 cies, on the authority of a specimen contained in 

 the British collection at the British Museum, which 

 has been regarded as belonging to it ; but Mr. Ste- 

 phens thinks that this is rather referable to another 

 species, the Cnethocampa pityocampa, and, conse- 

 quently, that the claim of the former insect to be 

 considered as a British species is dubious. 



In order to prepare for the last moulting which 

 precedes the change to the pupa state, they arrange 

 themselves on a branch in the manner represented 

 in figure 1, page 54. In this position they remain 

 many hours, at the expiration of which time they 

 shed their skins. Immediately after this is accom- 

 plished, their hairs are of a white colour. In this 

 state they remain for more than twenty-four hours 

 longer without taking any sustenance. Having 

 completed their growth, they undergo their change 

 to the chrysalis ; but this is effected in the nest, each 

 caterpillar spinning for itself a cocoon, uniting their 

 hairs with the silk ; so that on opening a cocoon 

 just before the caterpillar changes to a chrysalis, 

 the former is scarcely recognisable, being com- 

 pletely smooth and divested of hairs. As in the 

 larva, so in the chrysalis state, these insects are 

 gregarious, fixing themselves as closely together as 

 possible (fig. 2, p. 54) ; the cocoons being attached to 

 and parallel with each other, and disposed in layers 

 E 2 



