My girlfriend discovered this remarkable, little larva ( 2,8 mm) when it was sliding along, belly-side up under the watersurface in my small ditch-water aquarium like a mini water-snail. The picture was taken from above, and so you see the belly-side. The little orange bulbs are watermites in a parasitic sessile stage. After some days they will let loose and then change into swimming mites. The larva resembles an ant-lion larva with its bulgy and warty appearance. It has a spheric back and a flat belly. The lava, being buoyant, is being pushed against the surfacefilm. As the legs pierce through this film, it is the tip of the abdomen which provides most of the propulsion in a caterpillar fashion. The purpose of this all is to get foodparticles from the surface with mowing movements of the bristled head. Notice the strong jaws: every now and then the larve throws it's head backwards, deeper in the water to catch a waterflea. It also strolls along algae and waterplants. The fullgrown larva is about 8 mm. I know nothing about the pupation, propably the larva crawls out of the water into the ditch-border. The beetle is also bulgy, it too crawls underneath the surface from time tot time. It is found in waters with much plants and likes mud and detritus. It can endure quit havy pollution. The female spins an eggsack: it is attached to the hind and middlelegs and carried for a while, in which the beetle can almost only use its frontlegs. Up till now I never have seen the beetle.