In my photo backlog with unidentified garden insects sat this odd duck. Its a water boatman, Hesperocorixa linnaei, a member of the Corixidae family. These bugs resemble backswimmers but as that name says those bugs swim on their back where this one doesn’t.

water boatman
(Hesperocorixa linnaei)

The bug swam in a green plastic bucket with a layer of water in it. After peddling around some time it took off again.

I can remember these critters from my childhood when I would frequently encounter them in swimming pools in France, where they would be peddeling on the bottom and in the corners where the dirt in the water would collect.