Hemimetabolous (or Simple) Metamorphosis

Hemimetabolism or hemimetaboly, also called incomplete metamorphosis and paurometabolism, is the mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage, or imago. These groups go through gradual changes; there is no pupal stage. The nymph often somewhat resembles the adult stage but lacks wings and functional reproductive organs.

Definition from Wikipedia: http://en.wikipedia.org/wiki/Hemimetabolism