SILK CULTURE. 5 



THE BIVOLTIN. 



The color of the newly hatched worm is black or dark gray, and it 

 gets gradually lighter till the last age, when it is of a cream-white color. 

 The worm passes through from three to four " molts" or sicknesses. The 

 periods between these molts are called "ages" — there being five of these 

 ages including the first, from the hatching, and the last, from the 4th molt 

 to the spinning period. The time between these molts is usually divided 

 as follows — the first period, from 5 to 6 days — the second, from 4 to 5 days 

 — the third, about 5 days — the fourth, from 5 to 6 days — and the fifth, from 

 8 to 10 days. These periods are not exact but proportionate. 



The time from the hatching to the spinning of the cocoons will vary 

 from 30 to 40 days, depending on the race of the worms, quality of food, 

 mode of feeding, temperature, etc., but the same proportion of time between 

 the molts is generally found to be the same. 



When moiling is about to take place the worm ceases eating, at which 

 time it firmly fastens iiself by its hinder legs — raises the fore part of its body, 

 and remains motionless for about 12 hours when it casts its skin. During 

 this time it must not be disturbed. 



When ready to molt the worm becomes of a dirty yellow color, and 

 care must be taken not to mistake them for the sick worm, which it some- 

 what resembles, and which will be described hereafter. In front of the first 

 joint a dark spot is to be noticed at this time, showing the growth of the 

 new head, and when this sickness or molt is over and the worm casts off 

 its old skin, it rests for a short time to recover its strength and then com- 

 mences eating voraciously, as if to make up for lost time. In molting the 

 new head is just freed from the old skin, which is then gradually worked 

 back until it is entirely cast off. This process is repeated until the 4th molt, 

 after which, in the course of 8 to 10 days' feeding, it will be ready to spin. 



All worms hatched on the first two days should be kept together and 

 called the ist hatch — those of the third day, the 2d hatch — and all the re- 

 mainder, the 3d hatch. This is to have your worms grow up together of 

 an average size, so as to molt at one time, and not to have the larger ones 

 crowding the smaller from their food. It is also advisable to separate the 

 larger worms from the others as they outgrow them. 



THE COCOON. 



The " Cocoon" is tough and compact, and is composed of a continuous 

 thread of silk which is strong and firm, and is spun by the worm in figure 

 of 8, shaped loops. Its shape is generally oval or egg-shaped, and varies 

 in color, the commonest of which are the yellow, straw or cream color, white 

 and green. These colors are supposed to denote the nationahty of the worm 

 spinning them. The larger sized rounder-formed cocoons denote the 

 females, while the males are more slender shaped, depressed in the centre 



