STATES OF INSECTS. (Larva.) 197 
count of the former is given quite in detail, as that of a 
person who is describing what he has actually seen: yet 
by a later and very able physiologist, Dr. Herold, it is 
affirmed that the inner skin of the intestinal canal is never 
cast, that canal constantly retaining its two skins. He 
further affirms, that they are only the /arge trunks of the 
Trachez that cast their skins, none being detached from 
their smaller ramifications*. When men so eminent for 
their anatomical skill and nicety, and for their depth and 
acumen, disagree, the question must be regarded as un- 
decided till further observations throw sufficient weight 
into one scale or the other. 
The larva which has undergone this painful process is 
at first extremely weak: all its parts are soft and tender ; 
even the corneous ones, as the head and the legs, are then 
scarcely more than membranous, and are all bathed with 
a fluid, which, before the moult, intervenes between the 
two skins, and facilitates their separation®: and it is 
only after some hours, or in some cases even days, du- 
ring which it lies without motion, that this humidity eva- 
porates, all its parts become consolidated, and it reco- 
vers its strength sufficiently to betake itself to its wonted 
food. Its colour, too, is usually at first much paler than 
before, and its markings are indistinct, until their tints 
have been enlivened by exposure to the air, when they 
become more fresh, vivid, and beautiful to appearance 
‘ 
* Entwickelungsgeschichte, &c. 34, 88. Swammerdam on the con- 
trary affirms, that ‘‘ on the hinder part of the cast skin where it is 
twisted and complicated, whoever accurately examines the skin it- 
self may still observe the coat that was cast by the intestinum rectum. 
Ubi supr. 136. col. a. 
> N. Dict. @ Hist. Nat. vi. 290. 
