This appeared on Boathouse Bay today in large numbers. Not hatching but blown on to the water. The troot loved them. What is it? Between 3 and 5 \16ths in length.
Looks like one of the horse flies, full cousin to Clegs :)
Fairly sure it's not a wasp, although I'd agree it's a hymenopteran. More likely one of the solitary bees (not all bees are hairy!).