SIL mulberry-leaves. These will be greedily eaten for about eight days, at which period the worm is seized with a lethargic sleep, for three days ; when it changes its skin.. The creature now begins to eat again for five or six days, till it becomes subjeft to a second sick- ness or sleep, of a similar dura- tion. A third and fourth stages of equal length succeed, so that in about 32, or 36 days, the silk-worra attains its full growth, being ia this climate from one to two inches, but, in the warmer countries, from three to four inches in length. After thcsefour successive revo- lu-tions, the insett devours its food with great avidity for five or six days longer; at the end of which it becomes sickly, and in a manner transparent, when itrequiresnofar- ther nourishment : at this period, it endeavours to find a convenient spot between dry branches, in a dark corner, and begins to sp'm ; whiding the silk which it dr;iws from its bowels, around its own body, in an egg-shaped, roundish ball, dtnominated a cocoon. h this state, the worm remains for .a fortnight, and upwards, inclosed in the centre of its silky habitation, whence' it bursts forth in the form of a whiti.sh moth, the wings of which are marked with yellow or brown lines ; each female lays from 3 to 500 eggs, within two or three days, when she dies without tast- ing any food ; and the male gene- rally perishes in 24 liours, after having propagated its species.- — It deserves to be remarked, that, during the first day of its labours, the silk- worm spins only the exte- rior, irregular texture, which is known, in commerce, under the name oi floret, or coarse silk, serv- ing lor inferioi: stockings, gloves. SI L [6, &c. On the second or third day,' it begins to manufatturefine, con- necled filaments, extending several hundred yards in length ; and, after this useful work, thi- creature com- pletes its task, by forming its oval solid case, that resembles thin parchment, and in which it rests with safety, till it emerges in the shape of a butter-fly. — Those co- coons, however, which are intended for the prodii6tion of silk; ought to be sele6led within a week, and exposed to a hot oven, in which bread has been previou.sly baked j with a view to prevent the worm from cutting the siik : on the con- traiy, such as are designed for breeding, ought to be carefully sclefted, namely, one male to each female; the cocoons of ihb former being somewhat pointed at one end, while those of t'le latter arc generally of a larger size. Having thus .statexj the yarious changes which silk- wunps under- go, we shall proceed to point out the most proper vegetables for their' subsistence. The best adapted for this purpose, are the leaves of the black and white Mulber- ry-tree ; and, though we have remarked, vol. iii. p. 241, that this tree did not prosper in Britain, yet we understand from later informa- tion, that it may be advantageous- ly cultivated, particularly in Corn- wall ; on which account the Board of Agriculture has been induced to recommend tlie breeding of silk- worms to the inhabitants of that county. As, however^ mulberry. lea^T.s cannot always be procuied in sufficient quantity, the insetts, if kept in a warm place, may be occasionally fed with those of let- tuces. The you^ig (neither moist nor withered), leaves of black- berries, vines, cowslips, ash, and F 'i prim*
