Sawfly Larvae

Steven, your and Christine's spottings do look a lot alike. They definitely both look like Perga spp., but from photos it would be hard to pin down the exact one(s). And yes, they do clump together, and writhe about when alarmed, to deter predators. We have cherry trees, so we get 'pear and cherry tree slugs', also a type of sawfly larvae. We find ash placed around the base of the tree helps, as the larvae over-winter in the soil around the tree. On the eucalyptus trees, we are more likely to have Gumleaf skeletonizers, which are moth larvae, and also high on the ick factor scale.