Caterpillars

The etymological origins of the word are from the early 1500s, from Middle English catirpel, catirpeller, probably an alteration of Old North French catepelose: cate, cat (from Latin cattus) + pelose, hairy (from Latin pilōsus).
Many caterpillars are cryptically coloured and resemble the plants on which they feed and may even have parts that mimic plant parts such as thorns. Their size varies from as little as 1 mm to about 3 inches. Some look like objects in the environment such as bird droppings. Many feed enclosed inside silk galleries, rolled leaves or by mining between the leaf surfaces. Caterpillars of Nemoria arizonaria that grow in spring feed on oak catkins and appear green. The summer brood however appear like oak twigs. The differential development is linked to the tannin content in the diet.