Silk museum - Pupa and cocoon

When the caterpillar or rather the silkworm is ready to metamorphose into a butterfly, he wrapped itself in a silk cocoon it had previously weaved. Then he turns into a chrysalis, intermediate state between the caterpillar and the butterfly. It is when the chrysalis begins to pull away from sides that cocoon is taken to make silk. As to the chrysalis, it is grilled and then eaten.
A complete metamorphosis : silkworm --> pupa --> silkworm moth takes about 20 days.