I think Chelepteryx collesi smooths out the outlines of the pupa, making it look like bulge on the trunk. @HelenCross : could you open them (carefully) and take the pupae into protective custody, and see what the adult moth looks like when one emerges in due course ?
Geez, I’d love to, but I saw it on a bush walk in a national park and am now 200km away. In any case, I think I’d need a license to collect from a NSW NP but I haven’t looked into the details.