An adult beetle usually has two pairs of wings, although, unless he is flying, you may see only the hard wing covers. The wing covers are the forewings. Underneath these are the hindwings. A beetle's forewings protect his hindwings and abdomen when he is on the ground or in the water. These wing covers meet in a straight line down the beetle's back when they are folded over the hindwings. If you remember this about the wing covers, it will help you to know whether you have found a beetle or some other insect.

WATER-SCAVENGER BEETLES
Another common water beetle is called a scavenger beetle. The adult of this group is black and shining. You will know he is not a diving beetle because he does not hang upside down at the surface of the water. He hangs at the surface with his head up. His antennae are very short, and are said to be club-shaped because they are so large at the outer end. You will think that you see another pair of long, slender antennae on the head of this beetle, but each of these is really a mouthpart, called a palp.

When the water-scavenger beetle swims down into the water, he carries a large bubble of air with him from the surface, which gives a shining, silvery appearance to the under side of his body. You will notice that the flattened legs of this beetle are fringed with hair. This makes the legs seem broader than they really are and provides a wider surface for pushing against the water.

­The adult water-scavenger beetles usually feed upon tiny plants, called algae, which form a green, slimy covering on rocks and logs.

The larvae of the water-scavenger beetles are carnivorous, and feed upon nymphs, larvae, tadpoles, beetles, and other animals. They are shorter, broader, less active animals than diving beetle larvae, and their jaws are noticeably adapted for chewing their food rather than sucking juices. They are fond of snails, and it is said that they will even saw away a portion of the shell with their strong jaws, in order to reach the soft body of the snail.