The water scavenger beetles (Hydrophilidae) are of oblong or rounded body shape, most of them are small-sized, but there are also very large representatives, e.g. up to 50 mm in the genus Hydrophilus. The species in the subfamily Hydrophilinae live in water, whereas the representatives of the subfamily Sphaeridiinae are usually found on the land in dung or vegetable detritus. A distinguishing feature of the scavenger beetles are their 6-9-membered antennae and the extended maxillar palps, which are designed to perform the normal task of the antenna (smelling and tasting). The antennae in turn are used for respiration. Upon surfacing fresh air is passed along the antennae to the elytra, where it is stored. Worldwide more than 2000 species have been described, in Germany 110 species are found.