Whirligig beetle

Last saturday I visited with a friend a place where there was a great pond.
I had seen another time, that there were these running beetles on the water,
so I took my camera with me.
In dutch they are named 'Writers' Schrijvertjes, as if they are writing on the surface of the water.
I also like the english name Whirligig beetle..whirling and twirling on the water....