T.C., via email.

Your rather stunning scarlet caterpillar belongs to one of the wedge moths, most likely the dusky wedge moth, Capusa stenophara. It is in the geometrid family.

While they seem to be green in their younger stages, they gradually become brighter coloured as they near pupation. Yours appears to have grown to pupation size. The adults (moths) are surprisingly dull and inconspicuous, mostly light greyish-brown, with a wingspan of about 5cm.

The caterpillar’s food plants include native peas and eucalypts, seemingly indicative of an adaptable caterpillar. Some species of caterpillars are very specific in their food requirements.