A very small fly with a body length of just 1.5 to 2mm. The wings are shortened, barely reaching the end of the abdomen, or shorter still, only reaching the end of tergite 2. Tergites 1+2 are long, forming half the length of the abdomen. The body is partly reddish-yellow with the abdomen shining black. The antennae are brown with thickened, pubescent black aristae.

Lush, damp places such as fens and wetlands with Carex, Scirpus and Typha. The adults usually crawl on plants close to ground level.

Adults can be seen from May to September.

Scattered records across England and Wales with a strong southerly bias.

The Spearwort Fields record of 30.9.2017 is the first for VC55.