276 INSECT ARCHITECTURE. 



the labour and materials of the three coverings, she loses 

 the form of a worm, her spoils drop all around the chry- 

 salis ; first throwing off her skin, with the head and jaws 

 attached to it, and the new skin hardening into a sort of 

 leathery consistence. Its nourishment is already in its 

 stomach, and consists of a yellowish mucus, but gradually 

 the rudiments of the moth unfold themselves, — the wings, 

 the antennae, and the legs becoming solid. In about a 

 fortnight or three weeks, a slight swelling in the chrysalis 

 may be remarked, which at length produces a rupture in 

 the membrane that covers it, and by repeated efforts the 

 moth bursts through the leathery envelope into the cham- 

 ber of the cocoon. 



" The moth then extends her antennae, together with her 

 head and feet, towards the point of the cone, which not 

 being thickly closed up in that part gradually yields to her 

 efforts ; she enlarges the opening, and at last comes forth, 

 leaving at the bottom of the cone the ruins of its former 

 state — namely, the head and entire skin of the caterpillar, 

 which bear some resemblance to a heap of foul linen."* 



Eeaumur was of opinion that the moth makes use of 

 its eyes as a file, in order to effect its passage through the 

 silk; while Malpighi, Peck, and others, believe that it 

 is assisted by an acid which it discharges in order to 

 dissolve the gum that holds the fibres of the silk together 

 (see p. 170). Mr. Swayne denies that the threads are 

 broken at all, either by filing or solution ; for he succeeded 

 in unwinding a whole cocoon from which the moth had 

 escaped. The soiling of the cocoon by a fluid, however, 

 we may remark, is no proof of the acid; for all moths and 

 butterflies discharge a fluid when they assume wings, 

 whether they be inclosed in a cocoon or not ; but it gives 

 no little plausibility to the opinion, that " the end of the 

 cocoon is observed to be wetted for an hour, and sometimes 

 several hours, before the moth makes its way out." f 

 Other insects employ different contrivances for escape, as 

 we have already seen, and shall still further exemplify. 



* Spectacle de la Natiu-e, vol. i. 



t Coiint Dandolo's Art of Eearing Silk-Worms, Eng. Transl., p. 215. 



