Photo 1: newly emerged. Photos 2-5 taken earlier on 24 January. Photo 2: the pupae still intact. Photo 3: I almost missed the small male under the wing of the larger female. Photo 4: the male and Photo 5: an empty pupae case.
Interesting that though the larvae feed on the White Cedar tree, they pupate under the bark of the nearby gum tree.
That is one reason why they are a pest. When they wish to pupate, mature caterpillars go walkabout, seeking somewhere nice to pupate. Some travel up to 50 metres from their food tree, invading homes, garages, sheds, cars, anywhere, in their search.
Numbers haven't been so bad lately but there was one year (perhaps 10 years or so ago) when the whole base of the White Cedar tree was covered in hundreds of caterpillars. Luckily have not seen them like that again.