Bombyx. The caterpillar of the Bombyx mori is well known by the name of silk worm. When full grown it is three inches long. It feeds on the leaves of the mulberry tree and the Osage orange, and spins an oval cocoon the size of a pigeon's egg, of a close tissue, usually of a yellow color but sometimes white. A single fibre is often 1,100 feet long. It requires 1,600 worms to produce a pound of silk. Greek missionaries first brought the eggs of the bombyx or silk worm from China to Constantinople in 565 A. D. In the twelfth century the cultivation of silk was introduced into the Kingdom of Naples, and several centuries afterward into France. In the seventeenth century silk worms were brought to the United States. [See Silk]