LEPIDOPTERA. 



157 



This was the beginning of a cocoon. Each triangular blade was 

 composed of a great number of small, thin, rectangular plates, taken 



Figs. 



123. Cocoon of Pyralis corticalis (magnified, proper size | inch). 



from the bark of the twig. The caterpillar detached with its jaws a 

 small band of bark, and fitted it on, and adjusted it with admirable 

 precision against the edge already formed. It then fixed it securely 



