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CHAPTER IV. 

 ON CLASSIFICATION AND NOMENCLATURE. 



IN the foregoing chapters we have confined ourselves 

 principally to the points of general agreement amongst 

 Insects, only noticing their discrepancies of structure 

 where the observation of these was necessary to render 

 the subject intelligible ; but we must now turn our 

 attention more especially to the differences which 

 these animals present amongst themselves, as it is by 

 means of these alone that we are enabled to classify 

 them. It must be confessed, however, that in the 

 original formation of a system, the characters of 

 agreement must be observed simultaneously with 

 those of difference, and perhaps the nature of the 

 different groups may be rendered more intelligible 

 by following out the synthetical method by which 

 they were originally formed. 



The root of all classification in Natural History is 

 formed by the species, which may be roughly defined 

 as an assemblage of individuals all possessing exactly 

 the same characters, and which are all supposed to 

 have originated from the same parents. The syste- 

 matic Naturalist therefore takes no notice of the 

 individual, which in his eyes is merely an example of 

 the species to which it belongs, and the latter thus 

 forms as it were the first step towards a classification. 



D2 



