After checking and organizing the relevant information, it was found that the color of the silkworm's blood is constantly changing:

In its childhood, the green silkworm keeps eating mulberry leaves, and since mulberry leaves are green, the silkworm has to eat a lot of mulberry leaves every day, and its blood is green;

This situation will last until the silkworm's middle age, that is, it is about to stop eating and enter into the silk spitting

This will continue until the middle age of the silkworm, when it will stop eating and enter the spitting stage. During the spitting period, the silkworm does not eat mulberry leaves, and its body turns into a transparent color little by little, so naturally, its blood becomes transparent. In the middle, if some silkworms are sick for various reasons, become "stiff silkworms", then its blood will become yellowish, like pus;

When the silkworm is in the cocoon period, if we cut the cocoon, the blood inside the chrysalis will become yellowish.

When the silkworm develops to a certain period of time, when the cocoon becomes a moth, its blood becomes brown.

The reason for this is that I think it is mainly related to the silkworm's food and the surrounding environment, as well as its own development and growth pattern. When the silkworm does not eat or drink all day, in a closed environment, its blood becomes the same as usual. This may be related to its own laws.

Attachment Pictures of the growth process of the silkworm:

Growth of the silkworm

Silk extraction of the silkworm

Cocooning of the silkworm

Breaking the cocoon and rebirth