INTRODUCTION 3 



families of butterflies which differ in minor points, but which 

 are all alike in having club-shaped antennae, in holding their 

 wings vertically when at rest, and in the general form of the 

 pupa characters in which they differ from those forms we call 

 Moths, which have typically feathery antennae pointed at the 

 tip, fold their wings horizontally over their backs when at 

 rest, and have dark, oval-shaped pupae. On the other hand, 

 Butterflies and Moths are alike in such important points as 

 the structure of their mouth-parts, the presence of minute 

 scales over the wing -surf aces, and in the complete meta- 

 morphosis characteristic of their development ; they are 

 therefore grouped together in the order Lepidoptera (Gr. lepis, 

 scale ; pteron, wing), though butterflies are separated in the 

 special sub-order Rhopalocera. 



Then again, in the general structure of the body, in the 

 number of legs present, in the possession of wings, and in their 

 method of breathing, Butterflies and Moths (Lepidoptera) 

 resemble Beetles, Dragonfiies, Bees, Flies, and Cockroaches ; 

 all these forms, therefore, are grouped together in the class 

 Insecta. 



Finally, Insecta resemble Spiders and Crustaceans (Lobsters, 

 Crabs, etc.) in having a hard shelly covering to the otherwise 

 soft body, and in having jointed limbs ; hence all these forms 

 are included in the phylum Arthropoda, one of the primary 

 divisions of the animal kingdom. 1 



The position amongst animals which we assign to the 

 Large White Butterfly may therefore be summarised thus : 



Kingdom -Animalia. 

 Phylum Arthropoda. 

 Class Insecta. 



Order Lepidoptwa. 



Sub-order Rhopalocera. 

 Family Pieridae. 

 Genus Pieris. 



Species brassicae. 



This scheme of classification is of course dependent on 

 our present knowledge, and is provisional only. The aim of 

 zoologists in making such a scheme has been to try arid 



1 Only certain of the obvious external characteristics have been considered 

 in this classification, but it should be noted that it is based also on 

 similarity of internal structure. 



