Some moths are farmed. The most important of these is the silkworm. It is farmed for the silk with which it builds its cocoon. The silk industry produces over 130 million kilograms of raw silk, worth about 250 million U.S. dollars, each year. Not all silk is produced by "Bombyx mori". There are several species of Saturniidae that also are farmed for their silk, such as the Ailanthus moth ("Samia cynthia" group of species), the Chinese oak silkmoth ("Antheraea pernyi"), the Assam silkmoth ("Antheraea assamensis"), and the Japanese silk moth ("Antheraea yamamai").