sentence: Caterpillars use silk to make nests or cocoons.
sentences_before: All caterpillars can make silk. The silk is made from the salivary glands. Silk starts out as a liquid in the salivary glands. The caterpillar draws out the silk into a small thread. The silk hardens as soon as it is exposed to the air.
concept_name: caterpillar
headings: Butterfly Life cycle Caterpillar