16 BRITISH INSECTS 



Pieris napi the three specific names having reference 

 to the kinds of plants on which the caterpillars feed. 

 The Latin names of insects often, but by no means 

 invariably, suggest some peculiarity of the species in 

 question. Their chief justification, however, consists 

 in the fact that they bear a precise meaning to the 

 mind of the student, no matter what his nationality 

 may be. The words " large white butterfly " might 

 lack significance to the German, the Frenchman, or 

 the Russian ; but if he had studied insects, he would 

 know at once what Pieris brassica meant. 



Linnaeus massed his genera into still larger groups, 

 which he called orders, and these again into classes. 

 These terms are still in use, but since Linnaeus's time 

 it has been found advisable to bring in another kind 

 of group the family between the genus and the 

 order ; while the large groups are often split up into 

 smaller ones, called sections, sub-orders, sub-families, 

 etc. It is important to remember that all these 

 divisions, although artificially contrived, are never- 

 theless intended to express our knowledge of the 

 "natural" affinities of insects. The several species 

 of the same genus are more nearly akin than species 

 which belong to two or more distinct genera ; the 

 hundreds (it may be thousands) of species which go 

 to make up a family are all bound together by definite 

 characters, which are not seen outside the confines 

 of the group ; and so on until we come to the class, 

 which comprises all the animals of the insect (alias 

 hexapod) type. 



