Instar

An instar is a developmental stage of arthropods, such as insects, between each molt (ecdysis), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or changes in the number of body segments. Some arthropods can continue to molt after sexual maturity, but these subsequent molts are generally not called instars.