STATES OF INSECTS. (Larva.) 191 
will not be without use if I add a few additional reasons 
which seem to me still further to prove the correctness 
of Swammerdam’s system, as far as it relates to that sub- 
ject. With regard to the mere formation of the skin 
from the rete mucosum, were this the whole question 
few would hesitate to adopt the sentiments of M. Herold : 
but when we come to consider further—that the number 
of moults of individuals of the same species is always the 
same, and that it varies in different species, and takes 
place at certain periods,—we begin to suspect that some- 
thing more than the mere formation of a new skin upon 
an old one being cast is to be accounted for; and that 
the law which prescribes its own definite number of skins 
to each species, must begin to act in the primordial for- 
mation of the larva. Again, the hazrs observable in the 
higher animals do not take their origin from the epider- 
mis solely, but are planted below it in the rete mucosum, 
or deeper*; so that the change of skin does not affect 
them ; but in the larvee of insects they are a continuation 
of that integument, since, when the moult takes place, 
they always remain on the rejected skin”: this is the 
case, also, even with spines. If you shave a caterpillar 
ready to change its skin, either partially or generally, 
you will find that the parts in the new skin that corre- 
spond with those that are denuded, are equally hairy 
with those that were not*; and if you pay attention to 
the new-clad animal, you will find further, that the hairs 
never grow after a moult. From hence it follows, that 
the hairs have their place and take their whole growth 
@ Cuvier Anat. Comp. ii. 596. N. Dict. d’ Hist. Nat. xxvi- 165. 
® Cuvier Ibid. 624. © Reaum. i. 182. 
