212 STATES OF INSECTS. (Larva.) 
though indeed that which seems most natural, is adopted 
by the caterpillar of the beautiful swallow-tail butterfly 
(Papilio Machaon) and others of the same family. This 
first forms the loop which is to serve for its girth, and 
then creeps under it. But the difficulty it has to surmount 
is, to keep itself from being entangled in the fifty or sixty 
fine distinct threads of which the girth is composed, and 
to preserve them all extended so as to be able to intro- 
duce its body beneath them. For this purpose it makes 
use of the two first pair of its legs, employing them as a 
woman does her hands in winding a skein of cotton, to 
collect and keep all the threads of its card unentangled 
and properly stretched; and it is often with great diffi- 
culty, towards the end of the process, that it prevents 
them from slipping off. When a sufficient number of 
threads is completed, the animal bends its head between 
its legs, and insinuates it under the collected loop, which 
by its annular contraction it easily pushes to the middle 
of the body. 
In about thirty hours after the larvee which girth them- 
selves have finished their operations, the skin splits, and 
the pupa disengages itself from it by those contractions 
and dilatations of its segments which have been before 
described, pushing the exuviz in folds to the tail, by dif- 
ferent motions of which it generally succeeds in detach- 
ing them. One would have thought there would be con- 
siderable difficulty in slipping the skin past the girth; 
but this, according to Reaumur, seems to be easily ef- 
fected ?. | 
If you are desirous of witnessing for yourself the ma- 
* For the above account see Reaum. i. Mem, x. xi. 
