I saw them in Canberra in the Botanic Gardens and in private gardens, and in Sydney on the Manly foreshore. Alex Wild noted them from his trip to Australia this time last year and has posted some much better pictures than mine, along with some basic information about the species.
A Plague Soldier Beetle on a Canberra garage wall.
I am quite disturbed by what I read in the comments to his blog post. Most of them are from random Australians who have discovered his blog by accident because they have large numbers of these beetles in their garden and were trying to find information about them. What bothered me especially was the number of these comments that begin with 'I love nature, but...' and go on to say that they are planning to exterminate the beetles immediately.
So -- even when presented with the facts from a clearly reputable authority that a) the beetles are not just harmless but positively beneficial, and b) they will be in plague proportions for only a few days, these people are not prepared to temporarily modify their lifestyle or behaviour in any way (except to remember to purchase an extra can of Mortein at the supermarket). I have to wonder what exactly it is that they understand by the word 'nature' and what they consider to be 'loving' it.
A minor plague on a Teatree Leptospermum sp in the Australian National Botanic Gardens.
Doing what they do best.
*to slightly misquote the Bard, in traditional tabloid manner.
**sorry, that's a feeble taxonomy joke, and you need to know about Willi Hennig to get it.