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 features are the long rostral and dorsal spines, sometimes augmented by further, lateral spines. These spines can be many times longer than the body of the larva. Crab prezoea larvae have been found fossilised in the stomach contents of the Early Cretaceous bony fish "Tharrhias". Copepods have six naupliar stages, followed by a stage called the "copepodid", which has the same number of body segments and appendages in all copepods. The copepodid larva has two pairs of unsegmented swimming appendages, and an unsegmented "hind-body" comprising the thorax and the abdomen. There are typically five copepodid stages, but parasitic copepods may