158 THE INSECT WORLD. 



with silk threads. Reaumur saw this caterpillar work and erect in 

 this way a large blade during an hour and a half. 



"When one sees," he says,* "an insect which, to construct a 

 cocoon, begins by collecting together an infinite number of small 

 plates of bark in order to compose of them two flat triangular blades ; 

 which, to gain its end, takes means that seem so roundabout, 

 although they are' the most suitable and the quickest it could adopt, 

 one is very much tempted to consider such an insect, when one sees 

 it thus acting, possessed of reason." 



These two blades are at last transformed into a regular cocoon. 

 The little animal, which is at the same time architect, cabinet-maker, 

 and weaver, arranges it in such a way as to form a hollow coiie, which 

 it only remains for it to shut. Re'aumur calls this sort of cocoon 01 

 shell, la cogue en bateau, the boat-shaped cocoon. Some caterpillan 

 weave cocoons of the same form with pure silk. 



To bring this subject to an end, we will mention the industry 

 the Puss Moth {Dicranura vi?iula), and that of a small Tinea, whicl 

 eats the barley stored away in our granaries. 



The larva of the puss moth employs in the construction of its shel 

 the wood of the tree on which it has lived. It bites it up, and mixini 

 it with a glutinous fluid which it secretes from its mouth, reduces it t 

 a sort of paste, which it then uses in the formation of an envelope, c 

 such hardness that a knife can hardly cut into it. 



The Tinea lines the interior of a grain, of which it has previousl 

 devoured the contents, with a coating of silk, and divides it thus int 

 two different chambers. In one of these it is to change into a pupa 

 in the other it places its excrement. And so the Httle carefi 

 architect constructs its house in such a manner as to find in 

 tranquillity, cleanliness, and comfort. 



When caterpillars have not within their reach the materials the 

 are in the habit of employing, like good workmen, they content then 

 selves with what they can get. Reaumur reared a caterpillar whic 

 formed its cocoon of pieces of the paper of which the box was mac 

 in which it was imprisoned. 



What an extraordinary condition ! what a strange phase of vitali 

 does the chrysalis present to us — a being occupying the middle sta 

 between the caterpillar and the perfect insect ! How little does 

 resemble that which it previously was, and what it will become ! .' 

 appearance it is scarcely a living being ; it takes no nourishment, ai 

 has no digestive organs ; can neither walk nor drag itself along, ai 



* Mem. 12, vol. i., p. 487. 



