"The
Whirligig-beetles are easy to recognize on account of their characteristic
circular gyrations when disturbed, and by their habit of associating in large
numbers in quiet places. When one of these groups is disturbed they exhibit such
activity that they well deserve their name, "Crazy-bugs." The eyes of these
beetles are very peculiar in that each eye is divided into an upper and lower
part. Thus the insect has practically an upper and lower pair, one adapted for
sight at the surface, and the other for vision under water.
The Whirligigs do not seem to be very particular about their food, as they will
accept both live and dead insects which fall into the water, and even under some
circumstances will feed upon plants. When a beetle plunges beneath the surface,
as he often does when frightened, he carries down a small bubble of air between
the ends of his horny wings and the tip of his body. On account of his body
being lighter than water it takes some effort to dive, but none to rise to the
surface. The two hind pairs of legs which are used so much in swimming are very
much flattened and plate like, making excellent paddles, as is shown by their
exceedingly rapid movements." (Courtesy Charles C. Adams)