ENTOMOLOGY. 
7D 
acted upon by other authors. But in the present 
state of our knowledge, a classification of this nature 
appears premature, there not being a sufficiency of 
facts and observations on which it can be satisfac- 
torily founded. 
The orders in which the larvse have a strong re- 
semblance to the perfect insect, are Hemiptera, 
Orthoptera, and certain genera of Neuroptera ; in 
all the others, with a few exceptions, there is no 
resemblance between the tw r o states. 
In every instance insects may be considered as 
composed of thirteen segments, including the head, 
but in matured examples these are often 'merged in 
each other, owing to the disproportionate develop- 
ment of certain parts. In larvse the mode of life, 
movements, &c. being more uniform, an enlargement 
of one segment is seldom made at the expense of 
another, and we accordingly find the normal number 
distinctly marked. They are most regular and uni- 
form, however, in such as bear least resemblance to 
the winged insects they produce, although they can be 
traced without difficulty in nearly all other instances. 
The three segments immediately behind the head 
correspond respectively to the prothorax, mesothorax 
and metathorax of the perfect insect, and bear the 
three pair of legs (when these happen to exist,) 
which have been called the true legs, because they 
are persistent, to distinguish them from the abdo- 
minal or prolegs which are caducous and peculiar to 
the larvse. The curious structure of the latter has 
