XXIV INTRODUCTION. 



always reproduced : in this state the insect is inca- 

 pable of producing its kind. 



In the state of pupa, nymph, or chrysalis, the 

 insect is ordinarily incapable of taking food, and 

 contains within itself a sketch of its ultimate form. 



Naturalists have described various states of 

 metamorphosis ; all these, however, may be reduced 

 to two : 1. Partial metamorphosis, in which the 

 insect does not vary in its form in such a way as 

 not to be recognised in all its states as the same 

 individual. 2. Complete metamorphosis ; in which 

 the pupae take no food, are incapable of motion, 

 and the change is such, that nothing but the evi- 

 dence of sense could convince us of the identity of 

 the insect in its first and its last state. 



