A rack or ladder for silkworms to spin on
After the fourth moult the worms pass into the last age. Five or six days of voracious feeding brings them near that most dramatic event in their lives—the cocoon spinning. For three days, now, instead of eating steadily they wander aimlessly about, as if seeking they know not what; they wag their heads; they behave in an altogether restless and uncertain way. Is it some mortal ailment or mere "weakness of intellect?" You are expecting this and have prepared for it beforehand. They will not need to search long for a place to mount and spin in safety and security their cocoon of shining silvery silk. Farmers' Bulletin, No. 165, recommends the use of small, clean, leafless brush tied together into bundles and fastened between the shelves in rows a foot or so apart. Some use a sort of rack or ladder of narrow strips of wood which should be placed upright on the shelf where the worms can easily find it. They spin between the slats. Any worms which seem not to be ready to spin with the others should be fed until they, too, feel the impulse to travel.
As the process of spinning takes some hours, there will be no difficulty in observing it from start to finish. You are entitled to this exhibition, for, without your constant care and feeding, these creatures would not have been able to develop. The dull, inactive silkworm has acquired wonderful agility, and without practice is able to weave himself into his sleeping bag with astonishing celerity, reeling out his twelve hundred or sixteen hundred yards of silk in one continuous thread. There are no knots or kinks in it. It is inaccurate as well as rather silly to refer to the cocoon as a shroud or burial casket, as some do. The creature inside is just as much alive as ever it was.
The cocoons with the live pupæ inside are called green cocoons. To prepare them for market they are usually subjected to heat either in the oven or by steaming. No water should touch the cocoons, neither should the oven be hot enough to brown them. After heating they should be dried in the sun or other heat. Open one when you think they may be dry; if they are, the pupæ inside can be rubbed into powder with the fingers. A good price per pound is paid for dried cocoons, but it takes five hundred or more to weigh a pound.
If you have never seen a moth emerge from its cocoon you should keep several of your cocoons. In eighteen or twenty days the moth comes out, usually in early morning. Invite your friends to have a look, too. Must the moth break the threads in getting out, or is the cocoon woven in a manner to provide a gateway when it shall be needed? How does the creature get out anyway, and what is it like when it first arrives in the open? Wonderful happenings must have been going on inside to make a winged moth out of that naked caterpillar. Something left in the cocoon rattles when you shake it. Examine the dried ball and you will recognize in it the cast-off clothes, hat, coat, socks, and boots that he had on when he shut himself in. There, too, is the brown shell he wore as a pupa. You may think you know these things by reading about them, but you do not, really. Hearsay is not the real thing in any realm of life, least of all in the realm of nature.