An adult is 9 - 13 mm long with 10 ridges along each elytron (wing case).
Seen April until October at night. Usually found banging itself against a light source.
more on this and similar beetles
Flies to light.
Seen most warm months.
Makes a chirping sound with rear legs and a deep hum when flying.
Adults are found rushing around on the water surface on slow moving or stagnant water, the larvae are found in the mud or bottom vegetation of shallow water in ponds and ditches.
Adults hibernate during the cold months.
More on Gyrinus natator, the Whirligig beetle and other water beetles