Drain Fly - there nearly 5000 species of drain fly! These are those tiny little flies we see hovering around a drains or moist areas. We would probably need a magnifying glass to explore these little flies closely as they are only around 2.5 mm long with a wingspan of 3 mm. On close inspection they have a furry appearance resembling them to a moth, but they are a true fly. They are harmless other than them causing some annoyance! Photographed in Co. Leitrim.