CLASS INSECTS. 



with silk, secreted by glands analogous to the salivary glands, 

 and prepared by means of winders hollowed out in its lips. 

 At other times it suspends itself by means of filaments (Fig. 

 369), or conceals itself in some hole. It is while the insect 

 is in this state of apparent repose that there takes place in 

 the interior of its body an active labour, the result of which 

 is the complete development of all its organization. Its in- 

 ternal parts soften, and by little and little assume the form 



Fig. 369. Chrysalis of the Machaon. 



which they are afterwards to maintain. The various organs 

 with which the adult animal is to be provided become developed 

 under the envelope concealing them, and when this evolution 

 is finished, it frees itself of this kind of mask, unfolds its 

 wings, which soon acquire consistence, and becomes a perfect 

 insect. 



Fig. 370. Papillon Machaon. 



532. As an example of these metamorphoses, we could 

 not choose a better than that of the bombyx of the mulberry; 

 for this insect, in the state of a larva, is for us of immense 

 interest. It is the silkworm, the rearing of which contributes 

 so powerfully to the agricultural prosperity of our southern 

 provinces, and whose products support so many wealth-pro- 



