In the process of change, it will always stay inside. Silkworms go through four growth stages from hatching, commonly known as four sleeps, and each sleep (one growth stage) takes one week, so it takes only one month for silkworms to mature and start cocoon formation, and it can be completed in about two days. The silkworm peeled its cocoon for the last time and became a pupa. About ten days later, it appeared in the form of a silkworm moth, came out of the cocoon and became a moth. Cocoon is a protective layer for silkworm babies to spin silk when they become moths after ten days. Generally, it is saccular, and the main colors of cocoon are white and yellow. Cocoon is the raw material of many high-grade silks and textiles, and can also be used as a medicinal material for decocting medicine.
The process of silkworm cocoon changing: After two days' labor, the early silkworm babies make their own nests, and finally vomit around them to ensure that they can be fixed, so that they can hatch quietly without external interference. In the middle stage, young silkworms begin to gradually become pupae after molting in cocoons. The pupa's shell is hard and generally brown. The silkworm baby, which has become a pupa in the later stage, is about to complete its last molting. Biologists believe that after the fourth molting, the silkworm babies will enter a longer dormant period. In this dormant period, the development speed of silkworm babies is very fast, which can almost reach several times the previous speed. At this stage, their body length is about 7cm, and their weight has also made a leap in stages, which is tens of thousands of times that of the first stage. After the fifth stage, the silkworm baby's body has matured, mature cells have been regenerated, and its physical characteristics will become more and more obvious. When a cocoon is drilled out, it usually spits out a lot of liquid and grows out slowly. At first, the head came out first, and finally it became a moth.
Therefore, it takes a lot of effort for silkworms to become moths. We often compare a person's hard struggle, and the final success is like a silkworm feathering into a butterfly, to express human awe of silkworm, which is not afraid of hardship and fatigue. So don't ruin the hatched silkworm baby just because it's fun for a while. It is not easy for them to cocoon and finally struggle out.