and the cocoons are ready for the silk manufacturer. Japan.
When it begins to spin, the silkworm chooses a corner, the fork of a twig, or some such retaining point for its first thread. The breeder assists it in this inclination, by spreading rape-stalks over the bed of caterpillars--or brush or straw.
It takes the caterpillar three or four days to change into a chrysalis. First it makes a loose, ellipsoidal case, and then, supported by this--meanwhile twisting and bending its body, which is all the time getting shorter--it forms the cocoon. The transparent, thick, fluid silk-stuff comes forth from the spinning glands, through the so-called spinning teats in its head stiffening in two separate threads. These threads, however, become instantly cemented together in the short duct common to both, in consequence of their coating of glue. The length of this double thread varies between 350 and 650 meters.
From seven to nine days after the caterpillars have spun, the cocoons are taken from their resting places. The best are chosen for breeding, and the pupae of the remainder are killed by being exposed to the sun or by steam or heated air. The cocoons are then dried or put away to be wound off of sold.--Rein, The Industries of Japan.