166 



INVERTEBRATE ANIMALS. 



Moths, and Beetles — pass through three stages, just as do the pre- 

 ceding, but these stages differ from one another very much in 

 appearance, and the metamorphosis is therefore said to be " com- 

 plete " (fig. 112). In these insects the larva is •worm-like, segmented, 

 and usually furnished with locomotive feet, which do not correspond 

 with the three pairs proper to the adult (see figs. 123, 124), though 

 these are usually present as well. Sometimes feet are wanting alto- 

 gether. The larva is also provided with masticating organs, and 

 eats voraciously. In this stage of the metamorphosis, the larvte 

 constitute what are popularly known as '' caterpillars " or " grubs." 



Fi;^'. 112. — ^liitainorplxosis of tlie Magpie-moth {PhalKna grossulariata). 



Having remained in this condition for a longer or .shorter time, and 

 having undergone rejjeated changes of skin, necessitated by its rapid 

 growth, the larva passes into the second stage, and becomes a pupa 

 (fig. 123 — see also fig. 112). In this stage the insect remains quies- 

 cent, unless irritated, and it is very often attached to some foreign 

 object, so as to be quite incapable of changing its place. In the case 

 of the Butterflies and Moths, the pupa constitutes what is familiarly 

 known as the " chrysalis." The body is protected by a chitinous 

 pellicle, and in some cases this is still further protected by the dried 

 skin of the larva ; whilst in other cases the larva — immediately 



