STATES OF INSECTS. (Larva.) 207 
both cases it should be observed, that the suspension of 
the pupa is the object in view; but as the process is the 
work of the larva, this seems the proper place for ex- 
plaining it. To begin with the jirst case. 
You are aware that all lepidopterous larvee have the 
faculty of spinning silk threads from their mouths, and 
it will readily occur to you that it is by means of these 
threads that they suspend themselves. But how? How 
is a caterpillar to hang itself by the tail to threads spun 
from the mouth? Even suppose this difficulty overcome, 
others still greater remain. Suppose the caterpillar to 
be suspended by its tail,—this is but a preparatory ope- 
ration,—what is required is, that the pupa shall hang in 
the same position: now when you take into consideration 
that it is incased within the skin of the larva, and without 
feet or other external organs; that it has to extricate it- 
self from this skin; to hang itself in its place, and to de- 
tach the skin from the threads which hold it—this will 
appear no trifling task. Indeed at first view it seems im~ 
possible. Country-fellows for a prize sometimes amuse 
the assembled inhabitants of a village by running races in 
sacks: take one of the most active and adroit of these, 
bind him hand and foot, suspend him by the bottom of 
his sack with his head downwards, to the branch of a 
lofty tree; make an opening in one side of the sack, and 
set him to extricate himself from it, to detach it from 
its hold, and suspend himself by his feet in its place. 
Though endowed with the suppleness of an Indian jug- 
gler, and promised his sack full of gold for a reward, you 
would set him an absolute impossibility: yet this is what 
our caterpillars, instructed by a beneficent Creator, easily 
