Colony of Red-line Gumtree Hoppers at the base of a ca. 7 year old Yellow Box (approx 10cm trunk diameter). There were also a few individuals and pairs dispersed on a low branch. There were no ants in attendance so it appears the bugs are not feeding, but they must be at least preparing to mate. The male in the second photo is holding onto the female with his middle legs while vibrating his front and backs legs, usually not touching the female. Many pairs in the main group were behaving in a similar way with varying degrees of contact. In one pair the male had his hind legs stationary but was stroking the "face" of the female with his front legs.
On small Yellow Box (coppice regrowth). Many adults (mostly paired) and nymphs on same tree and another nearby. Closest photographic match I have found on the web is Eurymelops rubrovittata, but this seems to be a different species. Host trees will probably be slashed by Parks Victoria soon as in previous two years.
Update: I have added another photo which shows the markings on what I assume to be the female. Since these match other photos on the web (including museum specimens on ala) I have changed the species to Eurymelops rubrovittata.