In this species the metacoxal plates are sharply pointed. It is 30 mm or more in length and the pronotum has narrow yellow borders front and back with the sides being only a little wider. Other distinguishing features are the underside of the beetle which is straw-yellowish with wide dark edges, the metacoxae & the last sternite are dark; the eyes have no pale rim and the scutellum has a yellow centre. The scutellum is usually dark in this species.
Unless identified by a recognised expert, photos are required from above and below. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.
Freshwater ponds and lakes and canals. It flies well and may also be attracted to light.
All year round.
Widespread in England and Wales, but seems to be rather local.
Rarely recorded in Leicestershire and Rutland.
Larger water beetles - a Dutch key but with very useful photos
Leicestershire & Rutland Map
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Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015