This caterpillar has special glands which secrete liquid silk through its lower lip. The liquid produced later hardens to form fine strands. The caterpillar makes its cocoons using these strands. The threads on the outside of the cocoons are rough, while those inside are soft and smooth.
Some fully-spun cocoons are heated. This kills the pupa inside. The cocoons are then put into hot water to loosen the fine threads. Finally, these threads are reeled off the cocoons.
The length of unbroken thread produced by a single cocoon measures about one-and –a-half kilometers. Being twisted together several of these threads make single woven materials.
