INSECTA. 



237 



tensive tribe of beetles, both terricolous and aquatic ; of the 

 former, we have an example in the common cock-chaffer (Melo- 

 lonthci), of which a figure is here given, as well as of the different 

 stages of its developement (fig- 106, A, B, c, D, E).* 



Fig. 106. 



Having thus introduced the reader to the chief orders com- 

 posing the vast class of insects, our next object must be to ex- 

 amine more in detail the principles upon which these animals are 

 constructed, both as regards their external organization, and the 

 nature and arrangement of their internal parts. We shall speak 

 of them in the first place only in their perfect condition, leaving 

 all observations relative to the metamorphosis to which they are 

 subject for subsequent consideration. 



* It would be foreign to our present purpose to do more than enumerate other orders 

 of insects which have been formed by different authors ; of these, the following are 

 the most important. 



Dermaptera (Leach), ^i^x t skin; vrngov) a wing. Earwigs (Forficula). 



Trichoptera (Leach), 6^ rp%os, hair; rrsgav. May-flies (Phryganea). 



Aphaniptera (Kirby), a<pav/jj, invisible ; vrr&gov. Fleas (Pulex). 



Aptera, arr^aj, without wings. Wingless insects. 



Parasita, (Latreille). Lice (Pediculus). 



Thysanoura (Latreille), 0v<rav-euos, bushy-tailed. Spring-tails (Lepismenae). 



