SILKWORM MOTH

(Bombyx), insect and source of commercial silk and an important member of the family Bombycidae (order Lepidoptera). Because of its centuries-old role in sericulture (silk production), the native Chinese silkworm has been introduced throughout the world and approaches complete domestication. The adult attains a wingspan of 40 to 50 millimetres (about 2 inches) and has a thick, hairy body. In its brief adulthood of two or three days, it does not eat and seldom flies. The female lays between about 300 and 500 eggs. Besides its natural food of mulberry leaves, the silkworm may sometimes eat the foliage of the Osage orange or lettuce. The pale naked larva has a characteristic caudal (posterior) horn. It attains a maximum length of 75 mm (about 3 in.) during a 45-day growing period. Pupation occurs within a cocoon that is made of one continuous white or yellow silken thread, averaging about 915 metres (1,000 yards). The thread is preserved intact for commercial use by killing the pupa with hot air or steam. The giant silkworm moth, or saturniid moth (q.v.), species belong to the family Saturniidae.