Silk- Worm. 339 



it, and the new skin hardening into a sort of leathery con- 

 sistence. 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 chamber of the cocoon. 



" The moth then extends her antennas, 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."* 



Reaumur was of opinion that the moth makes use of its 

 eyes as a file, in order to effect ita 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. 338). 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."! Other insects employ different contrivances for 

 escape, as we have already seen, and shall still further 

 exemplify. 



It is the middle portion of the cocoon, after removing the 

 floss or loose silk on the exterior, which is used in our 

 manufactures ; and the first preparation is to throw the cocoons 



* Spectacle de la Nature, vol. i. 



f Count Dandolo's Art of Rearing Silk-Worms, Eng. Trajisl., p. 215. 



