INSECTA. 



151 



motive feet, which do not correspond with the three pairs proper 

 to the adult (see Fig. 71, #), though these are usually present 

 as well. The larva is also provided with masticating organs, 



FIG. 64. Metamorphosis of the Magpie-moth (Phalcena grossulariata). 



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

 larvae constitute what are popularly known as " caterpillars " 

 or " grubs." Having remained in this condition for a longer 

 or shorter time, and having undergone repeated changes of 

 skin, necessitated by its rapid growth, the larva passes into 

 the second stage, and becomes a pupa (Fig. 64 see also Fig. 

 71). In this stage the insect remains quiescent, unless irri- 

 tated, 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 so 

 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 ; while in other cases 

 the larva immediately before entering the pupa stage spins 



