I have this fly and finally found out what it is, Sciara analis. We have no entries in the Family Sciaridae yet, I don't know if it is called a Sciarid fly or Dark-winged Fungus Gnat or neither.
There is only sites from Continental Europe come up with a search, none at all with a UK google, I guess this is another of those fllies we are not supposed to have but do.
I've check many sites and apparently, there is no common name for them.
Thanks macc, I just searched for 'dark-winged fungus gnat' and came up with some others that are small, the one on the next site is only 1/8" long, or 3+ mm.
http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note29/note29.html
Sciara analis is a little bigger, I read 8mm and that would seem about right. The common names for the Family don't seem to fit this one as a sciarid fly or gnat.
I think I have found the ansewr on the Encyclopaedia Brittanica. Where the normal fungus gnats or sciarid flies live in damp compost and attackplants, this one attacks mushrooms which is also a fungus! The common name there is given as mushroom fly or dark-winged fungus gnat.
Sciara is mentioned there, so that's what I will call it.
http://www.britannica.com/eb/article-9035671/fungus-gnat
I got the red message, although there is a Family there are no entries and it won't take mine, Ken help!
