These grubs are not true Caterpillars, but are the larvae various types of beetles. The grubs all look alike: white with a pale brown head, and they adopt a curled shape like the letter 'C'. They are found under the ground where they feed on various roots. They grow to a length up to 4 cms.

The adult beetles are very varied in appearance, from brown to green, with a length of 2 to 3 cms. One beetle of this family, familiar to people in Queensland and New South Wales, is the Christmas beetle : Anoplognathus olivieri.

Christmas Beetle: Anoplognathus olivieri.
(Specimen: courtesy of the Macleay Museum, University of Sydney)

Further reading :

Densey Clyne,
The Best of Widlife in the Suburbs, Oxford University Press Australia 1993, pp. 17-21.