SPINNERS AND WEAVERS 13 



appears in the secretion by the moth of a strongly 

 alkaline fluid which softens the cracked cocoon 

 sufficiently to enable the insect to push through ; 

 but a fluid sufficiently strong to so act on this hard 

 material would probably injure the moth if its 

 head were not protected by this cap. Several of 

 the near relations of the Puss Moth make similar, 

 though smaller, cocoons on bark, but others descend 

 to earth, and these caterpillars spin only a flimsy 

 cocoon, sufficient to hold the surrounding earth 

 particles together. 



One of the caterpillars of the Puss Moth group — 

 the Dragon {Hybocamfa milhauseri) — constructs a 

 cocoon of the solid silk kind, and to effect the exit 

 of the moth the chrysalis is provided with a 

 hard head-spine. The cocoon is made to fit the 

 chrysalis closely, so that when the time comes for 

 the emergence of the moth the chrysalis is able to 

 rotate the fore-part of its body, and the spine thus 

 travels over the same part of the cocoon until it 

 has cut out sufficient space to allow of the moth's 

 exit. The process — which has been fully described 

 by Dr. T. A. Chapman — is helped by the pouring 

 out of a softening fluid guided to the right place 

 by the same spine. 



The caterpillars of the Oak Egger family spin 

 firm, close-textured cocoons of an oval shape, 

 mostly attached to twigs or leaves, and with the 

 hairs from the spinner's body interwoven with the 

 silk. These cocoons are in some cases given the 

 appearance of egg-shell by the caterpillar ejecting 



