Veliidae

Veliidae is a family of predatory insects in the suborder Heteroptera. They are commonly known as riffle bugs, smaller water striders or broad-shouldered water striders because the segment immediately behind the head is wider than the rest of the abdomen, unlike in the typical water striders (Gerridae), close relatives which are also in superfamily Gerroidea. Unlike some Gerridae, riffle bugs are small, typically about 4.5 mm in length.