HYALOPHORA PROMETHEA. 137 
fine light yellowish brown silk, extending this coat- 
ing, with great skill and foresight, over the footstalk 
of the leaf, and attaching it firmly to the branch, so 
as to secure the leaf from being separated b}' any 
accident. This preliminary operation having been 
accomplished, the caterpillar next draws the edges 
of the leaf together ; thus forming a perfect external 
covering or mantle, in which it spins a fine strong 
durable cocoon of fine silk. In this habitation our 
little architect passes the winter, secure from birds 
and other enemies. (This is attempted to be repre- 
sented in the upper right-hand figure of Plate XII.) 
As soon as the cocoon has been completed, the 
caterpillar again sheds its skin, and is transformed 
into a pupa or nymph, as represented in the par- 
tially opened cocoon figured in Plate XII. fig. 2. At 
first, the leaf enveloping the cocoon remains green, 
but soon changes to a red or brown colour, when it 
becomes brittle, and is gradually carried away by 
the \vinds and storms of the winter, until finally 
nothing remains except the cocoon itself, which is 
firmly suspended by the silk which once covered 
the footstalk of the leaf. The instinct of the cater- 
pillar, in thus providing for the permanent attach- 
ment of its future habitation, appears to be superior 
to that shown by many other species. 
" The caterpillar is of a delicate green colour, 
with yellow feet ; each segment of the body, except 
the posterior, is marked with six blue spots, from 
which arise small black tubercles; in the second 
and third segments, however, the two centre tuber- 
