Saw a couple of these chaps while out walking my dog. Initially thought they were some type of miniature moth (because of the mother-of-pearl sheen from their wings). Anyway, as I shaped up to take a pic it was immediately obvious that it was actually more like a lacewing than a moth. A quick check in my Collins field Guide identified it as a male scorpion fly (probably a Panorpa sp.)
It's very obvious why they are called scorpion flies although only the males have the upturned abdomen. I have no idea what the purpose of the "sting-like" tail is. Apparently they are partly carnivorous but are quite harmless to humans.
It's quite small ~14mm according to various reference works.
Both pics hand-held Minolta A2 ISO 64, pic1 1/80 at f/3.5 (2 pics manually merged in CS2) and I used flash on pic2 only.
Bruce

