When swimming, sunburst diving beetles (Thermonectus marmoratus) and other members of the family (predaceous diving beetles) kick their hind legs simultaneously.
They require at least a temporary water source. If the one they inhabited dries up, these diving beetles will fly until another water source is located. These beetles feed on other aquatic invertebrates including mosquito larvae and pupae.
Ponds and lakes from California to Texas
They are powerful swimmers, and are able to stay under water for extended periods of time because they collect an air bubble under their wings that can be seen at the tip of their abdomen when they dive.