Both the Latin and common names of this family refer to the beetles' habit of swimming quickly and erratically, with occasional twirlsa practice that helps prevent predation. Whirligig beetles can also release a chemical from the apex of their abdomen that repels predators and which may be an alarm pheromone. The substance, which smells like apples, also reduces the water tension and causes the beetles to move forward quickly on the water's surface.
Anatomically, Whirligig Beetles are notable for having each of their two eyes divided into two separated parts, one above the water line and one below the water line, for a total of four apparent eyes. The clubbed antennae are short. The head, thorax, and abdomen form one continuous outline, viewed dorsally (Evans, 2014).
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