430 LECTURE xviir. 



The larvae of the Coleoptera are active, although some, as the 

 nut-v5^eevil, are apodal, like the larvas of the bee. In most of the 

 herbivorous species the thoracic legs are represented by fleshy 

 tubercles ; but the larvas of the carnivorous beetles have J;he thoracic 

 legs more completely developed before quitting the ovum. The head 

 is horny, and the trophi are well developed in all : the jaws frequently 

 resemble those of the perfect insect, as in the Carabidce, the larvae 

 of which likewise have antennae. 



The circumstance of most physiological interest in the develop- 

 ment of the Coleopterous order of insects is the great length of time 

 during which the species actively exist in the vermiform or larval 

 stage of their development. The larvae of the cockchafer typify the 

 earth-worm in their habits, and continue for three years burrowing 

 in the soil and devouring the roots of grass and other vegetables. 

 The larva of the stag-beetle bores its way into the trunk of a tree, 

 generally a willow or oak, and remains there six years. It is fur- 

 nished with two powerful jaws, with which it gnaws the wood. It 

 forms a cocoon of the minute chips or tan, to which it reduces the 

 wood, and passes a considerable period in the pupa state ; during 

 which, the large horns of the male are folded upon the breast and 

 abdomen, protecting the antennae and legs. 



The anatomy of an insect in its different stages of development, 

 and the changes of both the external and internal parts in the 

 progress from the larva to the imago state, have been most accurately 

 and closely examined in Lepidopterous insects. Many of these 

 changes are shown by Hunter, in his extensive series of preparations 

 of the silkworm moth (Prtps. 2976 — 3037). They were investigated 

 by Lyonnet in the Cossus ligniperda. They have been described 

 and illustrated with much accuracy and detail by Herold in the Papilio 

 brassicce, and by our own indefatigable entomologist, Newport, 

 in the Sphinx ligustri, and other insects. The larvae of the Lepi- 

 doptera quit the egg with a scaly head (Jig. 159, b) and jaWs, with 



Sphinx Ligustri. Larva. 



three pairs of thoracic legs, short, and with claws (o, p, q), and 

 usually four pairs of tubercular prologs (r, r), supported by the sixth, 

 seventh, eighth, and ninth segments ; sometimes there is also a fifth 



