Caudata Whitegrub

Size about 20mm. When we heard a strange noise in our house we concluded that it must be starting to hail. We had monsoon-like rain this morning. It still didn't sound right for hail. When we checked outside, we were in the middle of a bug invasion. The air was filled and so was our lawn. These bugs had bumped into our house from about 8 to 8.30pm. In the afternoon, while weeding, I had found several of these bugs, too. Photographing them at night shed light on two more stunning facts. Firstly, one of the beetle (probably the female) showed at least two mites or ticks. Secondly, after mating one of the males produced some sputum, a greenish foamy substance out of its mouth. In my search for an identification, I found an almost perfect match in June Beetle, aka May Beetle or June Bug https://www.britannica.com/animal/June-beetle). The genus associated with the picture, namely Phyllophaga seems not to exist in Australia. Lepidiota caudata was the closest match in the same tribe. Let me know if I am wrong. Update 28/11/2016: The battering of our house by these bugs continued the following day. They seem to be responsible for a multitude of vertical holes in the ground all over our property. Lots of bugs were caught by our big spiders, and seemed happy enough to still mate. The spiders seemed to stay away. I also observed a robber fly (or similar, to be investigated based on photo) flying around with one of these bugs. One of the caught bugs clearly shows some infestation by ticks/mites once more. Update 20/12/2017: One individual was found trapped in a plastic bucket when I came back to our garden from my lunch break.