Stonefly is a weak-flying insect. It is not a true fly because it has four wings. True flies have only two wings. Stoneflies are sometimes found in great numbers along the shores of moving water, where they mate.
The name stonefly refers to the nymphs (young), which live under the stones in streams or along the shores of lakes or ponds. Trout and other fish eat the nymphs. Adult stoneflies are drab in color. These stoneflies measure up to 21/2 inches (6.4 centimeters) long. Adult stoneflies feed on small aquatic plants and animals, and cyanobacteria (blue-green algae).
