"Little fairy" generally refers to the state that silkworm has just changed from "insect" to "pupa", and the pupa skin is not completely browned. It is characterized by soft and thin skin, light green color, better taste and nutrition than pupae, so it is deeply loved by people. When silkworms just pupate, their body color is generally light yellow, and the pupa is tender and soft, which will gradually turn yellow, tan or brown, and the pupa skin will become hard. The body wing is yellowish-white to grayish-white, and the outer edge of the front wing is indented inward behind the apex angle, and the color of each horizontal line is slightly dark, which is not obvious. The end line and the wing vein are grayish brown, and the rear wing is lighter than the front wing, and the edge is slightly longer with scaly hairs. After about 12- 15 days, when the pupa body begins to soften again, and the pupa skin is a little wrinkled and brown cocoon color, it Silkworm pupa is edible, has high nutritional value and is a good food.