2 THE BOOK OF BRITISH BUTTERFLIES. 



with a tiny spark of that same unfathomable mystery life 

 which reaches its highest manifestation in man himself. 



Our subject, then, is a branch of biology,* the science 

 that treats of life in its widest sense ; but this com- 

 prehensive science has two sides, which treat respectively 

 of life as it is manifested in animals on the one hand, 

 and in vegetables on the other. It is needless to say 

 that we are concerned with the former alone the animal 

 or zoologicalf side. 



Varied as are the members of the Animal Kingdom, 

 they may all be grouped into eight sub-kingdoms, the 

 highest of the eight containing the vertebrate* animals, 

 that is to say, those which possess a backbone and 

 internal skeleton ; while the animals composing the other 

 seven are invertebrate, having no internal skeleton. 

 Butterflies are found among the ^ Arthropoda^ the most 

 advanced of the invertebrate sub-kingdoms. 



The Arthropoda contain four classes, the most highly 

 organised being the Insects, || which may be distinguished 

 by their arriving at maturity after a series of changes, 

 called metamorphoses, when the outer covering is cast 

 off and a creature appears, as a rule utterly unlike 

 what it was before the change. An insect in the perfect 

 state may further be known by its being enclosed in a 

 jointed envelope and by having its body divided into 

 three parts : the head, bearing antennae, eyes, feeding 

 apparatus, &c. ; the thorax, bearing six jointed legs and 

 four wings ; and the abdomen. Butterflies fulfil these con- 

 ditions and are therefore insects. It should be observed 



* jSios (bios), life, \6yos (logos), an account, a description, 

 t Coi> (zoon), a living thing. 

 I Vertebra a joint. 



apOpov (arthron), a joint, TTOVS (po^^s), iroSos (podos), a foot; animals with 

 jointed legs 



|| Insecta, divided into (segments). 



