The Bag-shelter moth also known as the Processionary Caterpillar, is a member of the family Thaumetopoeidae

Thaumetopoeidae

Thaumetopoeidae is a small family of moths in the order Lepidoptera. The genera in this family have been historically treated as a subfamily within Notodontidae instead....

. Both the larvae and adult have hairs that cause irritation of the skin. The adults have brown wings that grow to be about 5.5cm wide. The larvae feed on Grevillea striata

Grevillea striata

Grevillea striata, also known as Beefwood, is a tree or shrub native to all Australian states, with the exception of Victoria and Tasmania...

at night and reside in brown silken bags during the day.

Behaviour

Ochrogaster lunifer is known as Processionary Caterpillar as they are often seen travelling in lines, one behind the next. However when disturbed they will curl up into a ball for protection.