Hemimetabolism or hemimetaboly, also called partial metamorphosis and paurometabolism,[1] 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 has a thin exoskeleton and resembles the adult stage but lacks wings and functional reproductive organs.[2] The hemimetabolous insects differ from ametabolous taxa in that the one and only adult instar undergoes no further moulting.[3]