Types of metamorphosis

Insects without metamorphosis (ametabolous)

Insects without metamorphosis (ametabolous). Larva and adult.
Silverfish

At eclosion, the insect resembles the adult, except that it is smaller.

Development therefore simply involves increasing the insect's size by going through successive moults.

Insects with incomplete metamorphosis (hemimetabolous)

Insects with incomplete metamorphosis. Eggs, nymph and adult
Exopterygota
(winged insects, the wings develop externally
on the nymph, or larval, body)

The nymph (or larva) resembles an adult without wings; the wings grow larger at each moult.

The larva reaches the adult stage at the final moult.

Insects with complete metamorphosis (holometabolous)

Insects with complete metamorphosis. Eggs, larva, pupa and adult.
Endopterygota
(winged insects, the wings develop internally
in the larval body)

At eclosion, the larva looks very different from the adult and it generally has a very different lifestyle.

When its growth is completed, the larva forms a pupa. Inside this protective envelope, the larva undergoes major structural changes, eventually emerging as the adult stage.