The pupa of the silkworm is shaped like a spindle, with three segments: head, thorax and abdomen. The head is very small, with compound eyes and antennae; the thorax has pectoral feet and wings; the bulging abdomen has nine segments. When the silkworm first pupates, its body color is yellowish, and the pupal body is soft and tender, gradually turning into yellow, yellowish-brown or brown, and the skin of the pupa is hardened. After about 12 to 15 days, when the body of the pupa starts to become soft again, the skin of the pupa is a little wrinkled and the color of the cocoon is brown, it will become a moth. The moth first secretes some lye, which dissolves the cocoon into a small hole, from which the moth breaks out and becomes a beautiful moth. There are two kinds of moths: female and male.