Host plant : Eucalyptus sp
https://www.projectnoah.org/spottings/1120676071
Larva found inside a gall growing on a young tuart tree branch (resprouting from lignotuber). Larva was approx 15mm long, gall was approx 20mm long (unfortunately did not remember to take a photo of the intact gall before opening it up)
Found like this on the ground. Under Euc leucoxylon (I think).
All on one Eucalypt. I think it is leucoxylon but am not 100% certain.