The insect (larva or nymph) between molts. Instars are referred to by number: the first instar is the stage between after hatching and before the first molt, the second instar occurs after the first larval (nymphal) molt but before the second, etc. Technically, the pupal stage (if present) is an instar, though it is not numbered like the others, and is simply referred to as the pupa. This term often is confused with’ stadium,’ a term restricted to the time interval of an instar.

See also, STADIUM, METAMORPHOSIS.