One of the Rove Beetles which have short elytra leaving most of the abdomen exposed. Full-sized wings are folded up under the elytra.
"Head, pronotum and elytra generally with metallic green or blue reflection; elytral surface between punctures very finely pitted; abdominal terga with vague elevation along midline (Distribution: southern New South Wales, Victoria, South Australia, Tasmania)"
First record for the Macedon Ranges.
Thanks to Nick Porch for the identification.
This is the adult beetle (from the previous two observations), one day after 'hatching', when I let it go and put it back on to the tree I had taken it from as a larva. It is thought by Martin Lagerwey to be Paropsisterna brunnea.