REMARKS UPON METAMORPHOSIS. 279 
of such as are exclusively founded upon metamor- 
phosis; and we therefore consider that metamor- 
phosis, however valuable in helping to distinguish 
large assemblies, is pushed much further than 
nature warrants, when it is used as the chief corner 
stone for the construction of genera and sub-genera ; 
which groups, if they are really natural, will always 
be distinguished by other and more intelligible 
characters. 
(189.) From what has been just said, it must 
not, however, be inferred, that the metamorphosis 
of insects is to be disregarded ; or that characters 
derived therefrom are not to be employed. The 
value of this and every other character depends 
upon the judicious skill with which it is used. In 
a group of unarranged animals, we can never know, 
a priori, what are truly its essential characters. It 
therefore becomes necessary to study all, that we 
may discover their relative prevalence, and there- 
upon make our selection. Another important ad- 
vantage will also result from such investigations: 
some characters will be brought to light, which, 
although not employed as essential distinctions of 
the group, will nevertheless throw considerable light 
on its analogical relations. A more beautiful 
instance of this cannot possibly be found, than in 
the subordinate types of the genera Amphrisius 
and Papilio, detailed at some length in our Zool. 1. 
second series. Each of these genera forms a circular 
group; and the contents of one intimately corre- 
spond with the contents of the other, not only in the 
form of the perfect insect, but even in the larva of 
all such as are yet known. It has been well said, 
Tt 
