What is a Caterpillar?
Don Herbison-Evans,
Stella Crossley

Caterpillars are the larval stage of LEPIDOPTERA (Butterflies and Moths) which are Insects. In general: Insects have six legs. All Insects progress through a number of stages as the grow. For LEPIDOPTERA, the stages are:
  • egg,
  • larva,
  • pupa, and
  • adult.
  • The larval stage of many insects is a grub. The larvae of insects in the order LEPIDOPTERA are unusual in generally having extra legs. In addition to their six true legs, they have up to ten prolegs. This makes them look and behave differently from the larvae of other orders of insects, so they have the special name : Caterpillars.

    six + ten = sixteen legs:
    a true Caterpillar:
    a Lepidoptera larva of:
    Helicoverpa punctigera
    only six legs:
    not a Caterpillar,
    but in this case:
    the larva of the Sawfly
    Perga dorsalis
    fourteen legs:
    not a Caterpillar,
    but in this case:
    a Velvet Worm
    no legs:
    not a Caterpillar,
    but in this case:
    a Ragworm

    Some Caterpillars turn into butterflies, but most turn into moths, as in Australia there are only about 400 species of butterflies whereas there are over 10,000 species of moths. Many Caterpillars also appear to turn into flies or wasps, but that is because they have been parasitised by the grubs of these insects.

    Link to
    Frequently Asked Questions about Caterpillars

    Australian Butterflies
    Australian Moths

    (updated 12 January 2012, 14 June 2018)