SUPPLEMENT. 167 



becomes thinner. If at the time when the silk worms enter 

 all together upon the moulting, there are some that move 

 about, and do not sleep, or that take little nourishment 

 when all the others eat with appetite, it is a symptom of 

 sickness. They must be quickly removed, for fear they 

 will corrupt all the others by their contact. Generally, a 

 very healthy silk worm sleeps upon the leaves. Those that 

 remain under the leaves are weak and lazy worms, that 

 make a very thin cocoon, or rather that do not know the 

 art of forming it. Those that throw their silk carelessly 

 and form too large a cocoon, are stupid, (sic,) and not lazy 

 worms. 



MEANS OF KNOWING THE SILK WORMS THAT ARE MATURE ENOUGH 



TO SPIN. 



When the silk worms have sufficiently eaten of the leaves, 

 it is very important to know the precise time when they are 

 ready for spinning. The silk worms generally hatch be- 

 tween eight and ten o'clock, it also commonly happens that 

 at the same period of the day they are ripe enough to spin 

 their cocoons. 



When a silk worm is mature, the two glands at the bot- 

 tom of its throat are clear and transparent. If they are too 

 young by one-tenth, when they are put in the cocoon room, 

 they will give very little silk ; if they are too old by one- 

 tenth, and they commence to let threads of silk escape, they 

 will never fail to make a thin cocoon. A well practised eye 

 is required to seize them at a proper time. Those persons 

 endowed with a perfect knowledge of the subject, are never 

 deceived respecting a single silk worm. It is extremely 



