Wikipedia
Deuterophlebia
The fly genus Deuterophlebia is the sole member of the small monotypic family Deuterophlebiidae or mountain midges. Adults have broad, fan-shaped wings, and males have extremely long antennae which they employ when contesting territories over running water, waiting for females to hatch. Larvae occur in swiftly flowing streams and are easily recognized by their forked antennae and the prolegs on the abdomen. One classification places this family in its own infraorder Deuterophlebiomorpha, but this has not gained wide acceptance. A recent phylogeny of the entire order Diptera places them as the sister group to all other flies.