What is a "stonefly"?

A stonefly is a freshwater insect found near streams and rivers. It has a flattened body, two pairs of wings, and long antennae. Stoneflies undergo incomplete metamorphosis, with nymphs living in water and adults living near water. They are herbivorous or detritivorous, and important indicators of water quality. Stoneflies have a short lifespan and serve as a food source in aquatic ecosystems.