The larvae of butterflies and moths look almost nothing like their parents. Caterpillars are fleshy with helmet-like head coverings made of chitin. In addition to 3 pairs of thoracic legs, 3-5 pairs of fleshy abdominal legs end in retractable hooks (crochets) that allow larvae to grab onto trees or other surfaces. A caterpillar hatches from an egg laid on a host plant chosen by its mother. It spends most of its time munching on the host plant- mainly leaves, but also stems, bark, or flowers. The caterpillar grows over a period of weeks, or in rare cases years, shedding its skin periodically (molting) like a shirt that has gotten too small. While growing, it employs defenses such as spines, irritating body hairs, or startling coloration to repel predators. A mature caterpillar activates the silk-making gland in its head and ejects silken threads through an organ (spinneret) on its lower lip to make a protective shelter. Whether a cocoon, a web, or a chrysalis, the caterpillar is able to use these as refuges while undergoing metamorphosis.