L 2<8 STUDY OF NATURAL HISTORY. 



must admit that his views on its relative affinities are 

 any thing but artificial. Metamorphosis, in fact, is 

 really one of the primary distinctions of the typical 

 Annulosa, but it is not the only one ; so, also, 

 is the structure of the mouth. Yet neither of these, 

 by themselves, will completely designate the typical 

 groups. We know, by experience, that every 

 peculiarity or variation in metamorphosis is almost 

 always accompanied by external differences in 

 structure, permanent in themselves, and always 

 within reach of observation. Why, therefore, should 

 we designate our groups by characters which are 

 evanescent, when the same object can be attained 

 by using others that are permanent? How is a 

 student, for example, to discover the natural tribe 

 to which any particular beetle belongs, and of 

 whose metamorphosis he is entirely ignorant, if the 

 tribes are to be characterised alone by their meta- 

 morphosis — that is, by the form of their caterpillar 

 and chrysalis ? The thing is manifestly impossible. 

 But the evils of assuming this theory as infallible 

 do not stop here. One of its most able and in- 

 telligent advocates has made metamorphosis the 

 basis of his arrangement of the Lepidoptera ; so 

 that, if this plan be generally adopted, we shall never 

 feel certain on the natural affinities of an insect, 

 until we have studied its larva and pupa. For our 

 own part, we must confess that we have the greatest 

 objection to such characters; and we think that 

 it is the duty of every naturalist to simplify the ac- 

 quisition of science, by choosing such characters for 

 his groups, as can be easily understood, and at all 

 times verified. Now this cannot, of course, be said 



