CLASS INSECTA. 



305 



some have simple eyes {ocelli), 

 which are usually placed on 

 the top of the head ; and some 

 have both kinds. 



Fig. sso. 



Facets qf the Eije of an Insect. 



Metamorphosis. — The young 

 insect passes through a series 

 of changes before reaching the 

 form of the adult. Thus, a 

 moth, on emerging from the 

 egg, appears as a larva ; if with 

 legs, a caterpillar; if without, 

 a grui or maggot. Its whole 

 business now is to eat, and 

 hence in this stage it is most diqestort appabatot op insects.— 

 injurious to vegetation. After l^'^^^-^^Ts^.^fTZ) 



repeated molts, to allow for g. Oizmra ; h. stomach ; I. Intestine; 



the enlargement of its body, it ^ZJa^: ^""'^ '"'"^' '' ^ 

 usually rolls itself into a co- 

 coon and becomes a pupa, during which stage it remains 

 quiet. At length, the time varying with different species, it 

 bursts forth an imago. It is now furnished with wings, and 



Mg. sss. 



Metamokfhosis op ah Ikbeot.— a. JEgg ; b. Larva ; c. I'upa. 



