Great Silver Water Beetle, Hydrophilus piceus of the family Hydrophilidae is one of the largest of the European Coleoptera, reaching 5 centimeters in length and 2 centimeters in width. The adults are omnivorous but favour plant material. In the UK a rare species mainly found in the Somerset Levels where it occurs in ditches. Aboard it occurs as far east as India. Extinct in Norway and Luxembourg!! and rare in several other countries.
Specimen Below. J.V. Blatchford. Sedgemoor, Somerset Levels. 15, September 1932. Bristol Museum coll.