THE YOUNG INSECT 27 



cats the eggs. It then easts its skin, and is transformed 

 into a soft, short-legged grub, which feeds upon the honey 

 stored by its hosts ; while after its third moult it becomes 

 an erueiform maggot, with functionless mouth -parts and 

 atrophied legs, not unlike the bee larvae whose food it 

 purloins. 



Cases of this kind are termed hypermetamorphosis, 

 i.e. something over and above the form-changes which 

 metamorphosis commonly involves. They throw a light 

 upon the evolution of young insects in general. We 

 perceive that the active, campodeiform larva is the primi- 

 tive type, because in hypermetamorphosis it invariably 

 precedes the erueiform type, the latter being correlated 

 with congenial surroundings and a plentiful food-supply. 

 We are thus able to explain what, at first sight, seems a 

 paradox, namely, that while the larvse of the less highly 

 developed insects are active and capable, those of the 

 more highly developed species are inert and grub-like. 



The chief point to bear in mind is this : that the form 

 of the young insect is due, either directly or indirectly, to 

 the manner in which its food is obtained — directly in the 

 case of the mouth-parts, legs, and sense-organs ; indirectly, 

 where protective adaptations are concerned. The preda- 

 ceous nymph of the dragon-fly, or the larva of a ground 

 beetle, is wholly dependent for food upon its physical 

 endowments and powers of sensation, while it is inevitably 

 exposed to many risks in the course of its career. A 

 caterpillar, on the other hand, gets its food with little 

 effort, and is in measure protected by its surroundings. 

 The same remark applies with greater force to the maggot 

 of a flesh-fly which is literally immured in an abundance 

 of food, and to the grub of a bee or wasp which is pro- 

 vided with food by its parents or by the adult members 

 of its community. The principle is really one of degene- 



