Hypermetamorphosis

Hypermetamorphosis, or heteromorphosis,[1] is a term used mainly in entomology; it refers to a class of variants of holometabolism, that is to say, complete insect metamorphosis.

In many hypermetamorphic species, the first instars are numerous, tiny, very mobile larvae that must find their way to a food source.

The general term for a mobile first instar is a planidium, from the Greek language πλάνος (planos) meaning "roaming".

There is however, considerable variety in the forms of planidia that occur in various families and orders; in the beetle family Meloidae, the three-clawed planidium originally was called a triungulin, and similar planidia for example, those of the Strepsiptera, may also be called triungula.

[4] The prepupa or last larval instar of insects ceases to feed and (in some cases) searches for a place to pupate,[5][6] but this also is not considered hypermetamorphosis.

These planidia are fairly typical of certain species of parasitoid wasps, in this case the genus Perilampus .
Hypermetamorphosis in Meloidae. This form of planidium is a typical triungulin and feeds in its first instar. In its second instar it turns into a less triungulin-like form, and feeds again. It then turns into the Scarabaeoid form for two or more instars, depending on species. After that it adopts pre-pupal forms, pupates, and finally emerges as an adult beetle.
Triungulin on a butterfly. This probably is an example of phoresy rather than parasitism.