About Hydrophilus piceus (Linnaeus, 1758)
This species, Hydrophilus piceus (Linnaeus, 1758), is one of the largest aquatic beetles. Adult beetles reach 5 to 5.15 cm (1.97 to 2.03 inches) in length and up to 2.05 cm (0.81 inches) in width, while full-grown larvae can grow up to 7 cm (2.8 inches) long. Adult bodies are black, with a distinct greenish or olive sheen. They have protruding eyes and reddish-black antennae. This beetle is native to the western Palearctic realm, and occurs across most of Eurasia. Its range extends from Scandinavia down to the Mediterranean, North Africa, and Russia, and reaches as far east as India and China. Its distribution is not continuous, as it has been eliminated from certain areas. For example, it is considered extinct in Norway and Luxembourg. It is rare across many of its remaining regions, and is only found in specific relict habitats.
