Larva

A larva (Latin; plural larvae) is a juvenile form 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 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.

It is a misunderstandig that the larval form always reflects the groups evolutionary history. It could be the case, but often the larval stage have evolved secondary, like in insects. In these cases the larva might as well be more different from the groups common origin than the adults. Even in animals with a primary larval form it does not necessery show how an animal's remote ancestor once looked like, since this stage too often have evolved in its own direction just as the adult form has.

Names of various kinds of larvae:

hydrozoan	Planula
Fresh-water Mussel	Glochidium
Many crustaceans	Nauplius
Decapod	Zoea
Butterfly, Moth	Caterpillar
Beetle	Grub
Fly	Maggot
Mosquito	Wriggler
Bee	Schadon
Lamprey	Ammocoete
Eel	Leptocephalus
Frog, Toad	Tadpole, Polliwog