Wasp

Mac
This is a truly cool picture on many levels. There are actually two wasps in this picture and they are stuck together in a mating flight. The large, winged, black and yellow wasp is the male, and the smaller, wingless, brown wasp (which is mainly obscured by a leaf) is the female. The female attracts the male by releasing a chemical signal, and then they couple and stay couple for a while (during which time the male can actually fly around while joined to the female).
These are in the Tiphiidae subfamily Thynninae (a group which includes the Australian orchid pollinating wasps).
http://en.wikipedia.org/wiki/Tiphiidae

Thanks Leanne

Lovely MacC :)