Wing length 5.5 to 7.75 mm. Both sexes are immediately recognisable by the shape and markings of the abdomen – which widens steadily towards the tip and has a pair of pale yellow spots on segment T3 on an otherwise black background.

Wet meadows, and along the edges of water bodies such as ponds and ditches.

April to September peaking in June and July.

Widespread but local in Britain. It can be abundant where it occurs.

Local in Leicestershire and Rutland.