Scaled Hindleg Bigeye Fly

Size 3mm. A small fly with big eyes. It is probably very common. It is constantly performing a dance, going back and forth. Quite funny to watch. The fly is very visible because of its huge, red eyes. Body is dark-brown, quite bare, not with many hair. Abdomen segmented. Legs are cream-coloured, with the hind legs showing unusual scales rather than straight tibia and femur. Wings are transparent, with visible veins. Sides look like a thread of pearls rather than a smooth frame. Update 15/4/2017: Yesterday, I documented a fly that fulfills all criteria of an ID nightmare. The fly is similar size, behaves similar, looks similar. So many details match. Only: the eyes are not as big and the whole geometry of its head looks different, occuli wider apart on large black area between compoud eyes. Could it be a gender related difference? I simply have no idea. I found a matching record at http://naturewatch.org.nz/observations/1399482 which is placed in the same family but not identified any further.