This fly was identified by Ken Walker on Bowerbird website as being of Heteomyzidae spp., so I guess this was meant to be Heleomyzidae spp. The index of my fly book states for Heteromyzidae, to see Heleomyzidae. It is pictured clinging to an Allocasuarina.
This moth larva (Family: Psychidae (Case Moths)) was building its home. A couple of hours after this photo was taken, the case had a few more sticks on the outside and the end of the branch on the young eucalypt was cut off and lying on the ground.