The life cycle of dragonflies and damselflies is described as incomplete metamorphosis. This means the usual four stages of egg, larva, pupa and adult seen for example in butterflies are reduced to three: egg, larva and adult.
The lack of a pupal stage means that the dragonfly body develops gradually through a series of larval stages each more closely resembling the adult form. This is in stark contrast to the dramatic changes that take place during the pupal stage of an insect exhibiting complete metamorphosis, such as the butterfly. The links below explain each stage in more detail: