A small (2mm) water beetle with distinctive dark markings on a pale base colour. The large dark marking across the elytra generally has 4 'teeth' projecting forwards. It has two longitudinal furrows on the pronotum that extend onto the elytra and has sutural striae (alongside the suture) that extend to, or nearly to, to elytral tip.

Bidessus species have a similar furrow on the pronotum extending onto the lytra but the two Uk species have very different patterning.

A good image showing the patterning is usually required.

Still, lowland waters with exposed clay - often in the margins.

All year.

Reasonably common and widespread in England and Wales.

Reasonably common.

Apple Wildlife - Hydroglyphus-geminus