Definition of instar in English:



  • A phase between two periods of molting in the development of an insect larva or other invertebrate animal.

    ‘When the eggs hatch, the caterpillar enters the first instar (stage of development).’
    • ‘After the second moult, larvae preyed only on the first-instar nymphs of Libyaspis, while the larvae of later instars preyed on nymphs of a wide range of sizes.’
    • ‘The larval stage consists of four phases, or instars, with a complete molt between each instar.’
    • ‘At the end of the third instar, the larva wriggles out of its warble, falls to the ground, and burrows into the soil to pupate.’
    • ‘The life cycle of most metamorphic insects includes several sequential larval instars followed by a molt to a pupa, and then a final molt to the adult.’



/ˈinˌstär/ /ˈɪnˌstɑr/


Late 19th century from Latin, literally ‘form, likeness’.