CHAPTEK XIV 



ARTHROPOD A (continued) 



Class IV. : INSECTA 



INSECTS share with birds the domain of the air, 

 Characters anc ^ ^ e ^ r adult structure is specially adapted to 



this aerial life. At the same time, they all 

 undergo metamorphosis in 

 their development, and the 

 larvae are very varied in 

 their lives, some being 

 adapted to aquatic life, as 

 the caddis larva ; others to 

 life underground, as the 

 cockchafer grub ; others, 

 such as caterpillars, to a 

 life above ground but 

 sheltered by vegetation ; 

 and finally there are those 

 that live a passive larval 

 life, cared for by the adult 

 insects, as in the case of 

 the larvae of ants and 

 bees. A considerable varia- 

 tion is to be seen, therefore, 

 in the structure of the 

 larvae, and special larval 

 organs are frequently de- 

 veloped which are not to 

 be seen in the adult ; all 

 the larvae are alike, however, in having a segmented body, 



205 



FIG. 137. Diagrammatic dissection of an 

 Insect's Body. (After Schmeil.) 



To show (1) The head with mouth-parts, eyes, 

 and antennae ; (2) The thorax of three seg- 

 ments bearing wings and legs ; (3) The ab- 

 domen. Down the centre of the body is 

 shown the nervous system, and on either 

 side the tracheae (marked with transverse 

 lines) and the spiracles, s. 



