Hypermetamorphosis

Hypermetamorphosis is a variant of holometabolism, that is to say, complete insect metamorphosis. In hypermetamorphosis some larval instars are distinct from each other. As a rule the first instar is a planidium or triungulin, or is otherwise specialised for active mobility and is equipped to seek out the prey or host on which subsequent instars are to feed. In typical examples the first-instar larval morphology is campodeiform (elongated, flattened, and active) and in this form it does not feed. On locating its host it undergoes ecdysis, changing its skin and adopting a scarabaeiform (grublike) or vermiform (maggotlike) morphology. As a rule the subsequent instars are of more a less constant form and not highly mobile, being specialised for feeding and growth until the final instar must metamorphose into the pupal form.