INTRODUCTION. 
77 
proaching incapacity either to defend itself or to flee 
from danger, the caterpillar, having now completed 
its full growth, generally abandons the plant on 
which it fed, and seeks a secure retreat, or some 
fixed and stable object to which it may adhere. It 
is in consequence of this precaution that we so of- 
ten find chrysalides in the holes of old buildings, in 
the fissures of timber, 8cc. or attached to walls, posts, 
and trees, as the latter afford more permanent secu- 
rity than the weak and perishable herbaceous plants 
which so many caterpillars frequent during their vo- 
racious days. Having selected a proper place, the 
animal commences its curious proceedings, which 
terminate in the ejection of its skin, the evolution 
of the chrysalis, and the suspension of the latter by 
means of a cord of silk. As chrysalides are eus> 
pended in two different ways, either perpendicularly 
by the tail, or horizontally by means of a band round 
the middle, the proceedings of the caterpillars ne- 
cessarily vary accordingly, and it will therefore be 
requisite to advert successively to each. 
When the chrysalis is to be suspended by the tail 
with the head downwards, the first operation of the 
caterpillar is to cover a portion of the surface to 
which it is to attach itself with a layer of silken 
threads, which readily adhere in consequence of 
their viscosity. Each successive layer covers a 
smaller space than that which preceded it, so that 
they form, when completed, a little hillock of silk, 
approaching to the figure of a reversed cone. Into 
