406 



APPENDIX. 



all as innovation, have ever been the unceasing opponents of every 

 improvement in every age, in vain do they strive to obstruct its 

 progress and to cause a retrograde ; or, to stop its march, which is 

 onward and irresistible. 



CHAPTER II. HISTORY OF THE SILK-WORM. 



The silk- worm, or Bombyxmori, is a. caterpillar; its body formed 

 of twelve membranous rings; these rings support the legs, which 

 are sixteen in number, and in pairs. Six of these are in front and 

 inflexible, and situated beneath the three first rings, and are each 

 covered with a scale. The other ten are flexible and membranous, 

 their positions beneath the rings ; these are called climbers or hold- 

 ers, and are provided with sharp hooks or claws, to aid in climbing. 

 The head has a horny covering, like a scale ; the jaws are very 

 strong, the teeth sharp, serrated, or indented like a saw. The 

 mouth is vertical and peculiar, and not horizontal, as in most other 

 beings ; two broad objects in its forehead, which might be mistaken 

 for eyes, are but bones of the skull. The eyes are small, fourteen 

 in number, seven on each side of the head, and near the mouth. 

 The organs of respiration are eighteen in number ; equidistant, and 

 situated along the body, are the holes or openings, nine on each side, 

 which serve for breathing. 



The substance of which the silk is composed is a liquid, transpa- 

 rent gum, of a fine yellow color, and is contained in two separate 

 sacs, of slender dimensions. Each of these vessels is about tea 

 inches in length, and wound in the stomach in spiral folds : near the 

 jaws two ducts convey the silken fluid ; these, uniting in one, serve 

 to compose the silken thread, which is usually from 400 to 3 ,200 feet 

 in length. 



The eggs of the silk- worm are of a dark lilac or slate color. The 

 silk-worms are at first black and extremely small ; as they advance 

 in age and size, they cast off their outer covering or skin, usually 

 from three to four times, at different periods, according to the variety. 

 These successive changes are called moultings ; and the times inter- 

 vening are termed ages. In a colder temperature, the duration of 

 thes^ several periods is prolonged; but in a warm climate, the period 

 or season of the first moulting, which terminates the first age, 

 usually occurs on the fourth or fifth day of its existence ; the second 

 on the eighth or ninth day ; the third on the thirteenth or fourteenth 

 day ; and the last on the twenty-second day. At each of these crit- 

 ical periods., the silk- worms remain in a torpid state, eating little, or 

 absolutely nothing,for a day or more. At the end of about ten days 

 more from the last period, or in about thirty-two days from the be- 

 ginning, the insect, now fully grown, is about three inches and one 

 third in length, transparent, of a yellowish white or pearl color. 

 Having now completed their fifth or last age, they eat no more, but 

 ascend to the leaves or brush- wood, which are placed for the purpose, 

 and commence the formation of the cocoons ; and, in the construc- 

 tion of these, the insect works busily and incessantly night and day, 

 during four days. The labor finished, the insect in the centre be- 

 comes transformed to the chrysalis state> 



