Although there is quite a bit of variation in the metamorphosis occurring in different insect groups, there are two basic kinds of simple (incomplete) and complete.

During simple metamorphosis the wings (if present) develop externally during the immature stages and there is no prolonged resting stage before the last molt. The young in simple metamorphosis are termed nymphs and are similar to the adults usually being only miniature versions. Wings if present appear as bud-like outgrowths in early stages.