Over all length 30 - 35mm. The elytra and thorax are a glossy brown/black with yellow borders, the antennae and legs are dark reddish. In the male the elytra are smooth while the female's are longitudinally grooved.
Fresh still or slow moving water, normally with plenty of under-water vegetation. The adults and larvae are carnivorous eating fish, tadpoles and other small creatures up to their own size.
Status and distribution
Common and widespread throughout most of Britain though slightly less common in Scotland. Common in Nottinghamshire and at Netherfield Lagoons.
Best time to see
All year. Especially May and September.