The silkworm (Bombyx mori, lit. "raw silk of mulberry") is not a worm, but the larva of a moth that is very important economically as the producer of silk. A silkworm's diet consists solely of mulberry leaves. It is native to Northern China.
The silkworm is so called because it spins its cocoon from raw silk. The cocoon is made of a single continuous thread of raw silk from 300 to 900 meters (1000 to 3000 feet) long.
If the caterpillar is left to eat its way out of the cocoon naturally, the threadss will be cut short and the silk will be useless, so silkworm cocoons are thrown into boiling water, which kills the silkworms and also makes the cocoons easier to unravel. This harvesting has been done for thousands of years.
The adult moth has been bred for silk production and cannot fly. It is also called the silkworm-moth or mulberry silkworm. Because of its long history and economic importance, the silkworm genome has been the object of considerable modern study.