76 
INTRODUCTION. 
accomplished in a very short time. As if exhausted 
by its efforts, the caterpillar continues for a while in 
a state of inactivity, till the moisture evaporate from 
its skin, and the newly exposed parts become suffi- 
ciently consolidated. The colours which, before 
moulting, were pale and indistinct, soon become 
bright and well defined, and are often distributed in 
a manner different from those which adorned the 
rejected covering. Its strength and activity are soon 
restored, and the renovated animal, 
Nunc positis novus exuviis, nitidusque juventa, 
returns to its wonted occupation with even greater 
voracity than before. 
These changes take place at least three different 
times before the caterpillar attains its full maturity; 
and in many instances, it is probable that there are 
not fewer than five or six moults. After continuing 
in their reptile form for a longer or shorter period, 
according to the species, they prepare to enter upon 
a new state of existence, distinguished by attributes 
very dissimilar to those they previously possessed. 
This important and singular metamorphosis, by 
which a long cylindrical worm, possessing all the 
necessary organs of motion and nutrition, and em- 
ploying these with the utmost activity, is converted 
into an inert mass, without external organs, and in- 
capable of locomotion, or of receiving food, is pre- 
ceded by some preparations similar to those that at- 
tend a change of skin. As if foreseeing its ap- 
