Well I guess you can't see any.
But believe me, they're everywhere, the mosquitos of the swamplands.
This by the way is not Lobau but one of the last rather natural bayous in the park-like region of Prater, on the southern banks of Danube river and much, much closer to the living quaters of over a million Viennese.
The photo was taken a few days ago when the sun still did shine; for the last couple of days it was raining cats and dogs (which kept me indoors) - and I expect Lobau being flooded, dirty and muddy by the time I'll venture out again (which most likely will be on thursday when we've got a holiday in Austria). I am quite looking forward to it.