I’ve seen a longicorn beetle previously, but this one is different: it looks like the sheep longicorn, Monohammus frenchi or Dihammus ovinus, according to Brisbane Insects. Update: Chris McKay at CSIRO asked one of their experts, who says its Disterna plumifera.
Longicorn beetle, Disterna plumerifera, body about 3 cm long
Sometimes longicorns have very long antennae, much longer than this one does. The pattern is said to look like the wool of sheep, hence the common name. Sounds to me like that was a long night of trying to come up with a name in the museum basement. And I am familiar with museum basements.
The larvae (grubs) bore mainly into the branches of growing eucalypts. This can cause branches to fall off, and even the death of the tree if the infestation is severe. Fancy being nibbled to death? Me neither!
A-roving I will go 
Seems to me the name might relate rather, to the long horns resembling a Ram (especially photo 1). I think the wooly explanation is rather fanciful.
Denis Wilson
Hi Denis, yes, the “sheep” name is a bit of a stretch. There are about 1250 longicorn beetle species in Australia (according to CSRIRO’s “A Guide to the Beetles of Australia”), but this is the only one with the common name of “sheep” longicorn so I’m not confident about your theory. I’ve emailed a few people about the sheep name and will report back if I find anything out.
Hi Denis. Chris McKay at CSIRO asked one of their experts, who says its Disterna plumifera (no common name, thank goodness). Chris is doubtful about the sheep hypothesis.
Good example getting the facts before making the assumption. I was reading a few things you edited for WIRES back in the 90s. Good job, always.