Length 13 to 15 mm. Distinguished by the front of the pronotum, which has pointed angles that extend partly around the eye.

There are four UK Notonecta species and whilst they look broadly similar they can all be separated in the field from the different elytral markings. See ID Aids below.

N. glauca is most likely to be confused with N. viridis. Both have pale wing coverings (these are darker in the other two species). The front corners of the N. viridis pronotum are pointed and they extend partly under the eye. The front pronotum corners are more or less square in N. glauca.

A good photo of the dorsal surface is needed and ideally a side view showing the front corner of the pronotum. Alternatively the specimen needs to have been examined and the ID method described.

Often in brackish water but extending its range into silty bottomed freshwater pools.

This species has been recorded in most months of the year.

Widespread in England and Wales with few records from the far north.

Status in Leicestershire and Rutland not known.