The Lesser Water Boatman shown here is one of several species called Water Boatman and one of the two most commonly found in ponds and slow-moving water.
It swims on its front and is vegetarian; the Common Backswimmer, also called a Water Boatman, Notonecta glauca, swims on its back and eats aquatic insects and tadpoles/tiny fish.
The Lesser Water Boatman has two shortened front legs, two long middle legs and two back legs formed and used like oars when swimming. It also flies on summer evenings and is attracted to light.
Water Boatmen are true bugs. In order to breathe underwater, they take an air bubble down with them, like an aqua-lung.