242 NATURAL HISTORY. 
on the leaves of trees till August or September, and then 
descends to seek for some currant or barberry bush upon 
which it may build its house for its winter sleep. ‘ Any 
one,” says Professor Jaeger, “who meets with these 
caterpillars in the above-mentioned months may have 
the pleasure of witnessing their metamorphosis into co- 
coons, and several months after into an elegant moth, by 
taking them up very carefully upon leaves and carrying 
them home, placing them in a spacious box, with a little 
undisturbed earth at the bottom, and then putting into 
it some dry brush-wood, about one foot high, and cover- 
ing the whole with gauze in order to prevent their es- 
cape.” 
415. I will now describe the peculiar construction of 
the cocoon. That of the Silkworm is a simple cocoon, 
no special provision being made against the cold, as the 
pupa state, instead of lasting through the winter months, 
is finished in a few weeks. But in the case of the Ce- 
cropia Moth there is a covering outside of the proper 
cocoon. This covering is fastened to a branch of some 
bush, as in Fig.188. It is made very strong, as its fibres 
Fig. 188. = 
are much more closely joined together than those of the 
cocoon inside of it. Often there are leaves attached to 
it, leaving the impression of their veins or nerves upon 
it when you have detached them. The animal evidently 
uses these leaves as a sort of scaffolding when it begins 
to construct its winter home. In spinning this covering 
it works all the while inside, as it does in spinning the 
cocoon. After finishing it, it lines it with coarse loose 
