(1) An incomplete metamorphosis in insects.
(2) Incomplete or partial physical changes in insects, i.e. insects do not undergo pupal stage during their development from embryo into adult form.
Hemimetabolism refers to the incomplete metamorphosis in certain group of insects. These insects develop from embryo, to nymph and finally to adult. There is no pupal stage. The nymph often resembles the adult in which both of them have compound eyes, developed legs and wing stubs visible on the outside.
See incomplete metamorphosis for examples of hemimetabolous insects.
Word origin: Greek hémi- half + Greek metabole change + -ism
Related forms: hemimetabolic, hemimetabolous (adjective).
Synonym: incomplete metamorphosis, hemimetaboly, hemimetamorphosis.
See also: metamorphosis.