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. The Water-skaters, or Striders, prefer quiet waters, as do the Whirligigs, but do not have the decided social disposition, shown in the latter to such a marked degree. These Skaters, on account of their long legs and short bodies, are the "Daddy long-legs" of the water. These characteristics and their habitat make them easy to recognize. They are nervous, active insects in their movements, jumping and skimming about on the surface with but little show of grace and ease as compared with the ordinary graceful curves of the whirligigs. Their food habits are very similar to those of other surface insects, that is, dead and dying insects found floating on the water. But their method of taking food is quite different from that of the Whirligigs, because of the great difference in the structure of their mouth parts. The Whirligig, being a beetle, has the typical biting mouth parts, while the Strider has a slender beak or proboscis, by means of which it sucks the juices from its prey, as do other bugs. The fore legs are used to seize the prey and bring it within reach of the beak. The middle and hind pair are used for rowing over the surface, the latter pair, primarily, for steerage, the fine hairs on the legs making it possible, as mentioned before, to make use of the surface tension. Large dimples are formed on the surface of the water where the feet touch it. One would hardly expect it possible for an insect standing on the surface of water to get its feet dirty, yet the great care which they give to cleaning their feet clearly shows that dirt is of common occurrence, even there. The white or gray color on the lower side of the body is due to the reflection of light from minute hairs which cover the surface, and keep the insect dry even when submerged.