Like other caterpillars, silkworms shed their skins at certain intervals. The six-day period between hatching and the first moult is called "the first age." On the fourth day it is best to change the beds, as the droppings from the worms and the litter of uneaten leaves are not healthy for the moulting caterpillars. Spread fresh leaves on nets and place over the worms in the evening. By morning all will be ready for the clean shelf and doubled space. As the sixth day approaches, the worms lose appetite and cease to move about. Finally the skin whitens, the head seems to grow larger, and each little creature pulls himself out of his old skin and finds himself clad in a new suit. I imagine he must feel very much as a boy does when on the first really warm day in April his mother allows him to shed his winter underwear, get his hair cut short, and wear his summer blouse and knickers. The young worm, however, does not feel very lively at first. No food should be given for several hours. When signs of waking are evident, food should be given and the worms transferred to clean shelves by means of the nets. On the third day they should be changed to fresh papers. Four meals a day are needed by the caterpillars at this time. The second age is shorter than the first, being only four or five days. The skin now changes in colour from gray to yellowish white. After the second moult their food need not be cut much, but they require a lot of it, as they should double their size during the third age, which lasts six or seven days. If the weather is pretty warm their development is faster. They should never be crowded nor allowed to go hungry. Always change to clean shelves when the dead leaves and excrement become the least offensive. This odour, which you can escape by leaving the room, may be deadly to your pets. They are helpless to escape it, and are entirely at your mercy. During the fourth age, _i. e._, after the third moult, give more space and feed small branches with leaves on. Always remove every berry from the mulberry branches or the worms will eat them and be made sick. Their appetites are enormous, their growth rapid. Change the beds four times during this period of nine days. [Illustration: A rack or ladder for silkworms to spin on]