Well, you are partially correct. Chances are you already are familiar with the adult forms of many aquatic insects. The aquatic insects comprise the bulk of benthic macroinvertebrate communities in healthy, freshwater streams. These insects are mostly in their immature form and live their adult like on land, sometimes for only a few hours.
Metamorphosis is the change that occurs during the organism's development from egg to adult.
These immature insects are called larvae and the do not resemble the adults, and in fact, may look grossly different. These immature insects are called nymphs and they undergo a series of molts until the last decisive molt transforms the organism into an adult or imago in mayflies. There is no intermediate pupae stage where transformation occurs. The nymphs resemble the adults closely except for wing development. Contact Wayne Davis for more information.