31 I 175 ] 



inoultingg, and take place at different intervals, and continue for va- 

 rious periods, according to the climate or temperature in which the 

 insects have been kept, their particular nature, the quality of the food, 

 and the quantity and regularity with which they have been supplied. * 

 In this country, in a general way, the silk-caterpillars of four casts or 

 moultings, which have been, in all respects, properly treated, show- 

 symptoms of their first moulting on the fourth or fifth day after they 

 are hatched. 



The appearances which the worm assumes in the various stages of 

 its life, will be mentioned in the course of the details of its progress to 

 maturity, and therefore need not be here anticipated. 



Sometimes a part of the covering remains attached to the extremity 

 of the caterpillar, which cannot cast it off. The insect then swells or 

 enlarges in the part which is disentangled, while the other part of the 

 body continuing compressed, occasions its death. 



After having recovered from a moulting, the new skin is pale and 

 wrinkled; the insect appears much larger than before, owing to the 

 Foom given for distending its body under the new skin, and feeds with 

 increased activity. This increase of appetite is in proportion to the* 

 advanced age of the insect; but, after the fourth moulting, it is very 

 great, and the consumption of leaves is immense. The last casting 

 of the skin, which is visible, being finished, and the caterpillar having 

 attained its greatest size, and matured the silky material in its ves- 

 sels, it loses all appetite, ceases to eat, and consequently to grow, and 

 fhen diminishes in weight and size. It relieves itself of the contents 

 of the alimentary canal, which are now soft and green, instead of hard 

 and black as before, and contracts its skin, and whole body, to such 

 a degree, as to be readily perceptible. These appearances take place 

 about nine or ten days aftev the fourth moulting. The caterpillar 

 now begins to prepare for spinning the silky tomb in which nature- 

 has destined that it should enclose itself. It first wanders about, and 

 raises up its head, as if searching for a place to commence work, and, 

 having fixed on a suitable spot, it throw's out some loose tlireads, and 

 glues one end of them to an adjoining surface. These threads it 

 next conducts to another part, and then fastens them; repeating this 

 process, and interlacing them in various directions, until it has sur- 

 rounded itself with a slight and loosely spun netting. In the centre 

 efthis, when contracted into a space sufficiently small, it lays the 

 foundation of the interior cocoon. Fixing itself to some of the sur^ 

 rounding threads, it bends its body, and, by successive motions of the 

 head from side to side, spins a layer of silk on the side ojiposite to it; 

 when this is of the requisite thickness, the insect shifts its position, and- 

 repeats the same process in another quarter,! covering each layer, in 

 turn, with a new one, until the interior cavity is reduced to the size 

 desired. Thus, the silken thread which forms the cocoon, is not, as 



* III India, during- Summer, the moultings are finished in a few hours. — Anderson's 

 Bee, Edin. vol. 8, p. 39. 



t See Plate 5, iig^s.. 4 and 5, for a view of tKe precise, mode m whicjx the silk fibres 

 a*c laid. 



