The water beetle Graphoderus bilineatus is a member of
the Dytiscidae family. It grows to a length of between
14 and 16 mm and can be distinguished from the other
members of the Graphoderus genus by its dorsally
flattened body and the very broad yellow transverse
band on the pronotum. Both as a larva and as an
adult it lives in water, in most cases in large, standing
freshwater bodies with gently sloping banks and good
conservation status. It only leaves the water for a short
time to pupate and transform to the adult stage.
It is found across a large part of Europe but is generally
rare and populations are patchy. Because of its rarity and
the endangered status of its habitats, it is recognised
as a species of European conservation importance. It is
also extremely rare in Slovenia. The handful of recorded
sightings to date are limited to the north-eastern part of
the country, most recently the Mura basin.