Larva

A larva (Latin; plural larvae) is a juvenile from of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). 

The larva can look completely different from the adult form, for example, a caterpillar differs from a butterfly. Larvae also often have special (larval) organs which do not occur in the adult form. The larvae of some species can become pubescent without actually developing into the adult form (for example, in some newts). This is called neoteny.