Larva Larva A larva (plural: "larvae" ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form ("e.g." caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to environments separate from adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water
Crustacean larva long rostrum, and a spine on either side of the carapace; the first post-larva closely resembles the adult. Porcelain crabs have two or three larval stages, in which the rostrum and the posterior spine on the carapace are "enormously long". Hermit crabs pass through around four larval stages. The post-larva is known as the "glaucothoe", after a genus named by Henri Milne-Edwards in 1830. The glaucothoe is long in "Pagurus longicarpus", but glaucothoe larvae up to are known, and were once thought to represent animals which had failed to develop correctly. Like the preceding stages, the glaucothoe is symmetrical, and