Stonefly larvae (also called nymphs or naiads) are aquatic, flattened, with 6 sprawling legs and with a segmented abdomen bearing 2 long antenna-like “tails” (cerci). The antennae on the head are long, too. Gills are tuftlike and usually positioned at the bases of the legs, on the underside of the body. Each foot has 2 claws.
Adults have two pairs of wings that are clear, membranous, and finely veined and rest closely down the back of the body, the forewings covering the hindwings. Antennae are threadlike and long. Colors are usually dull, dark, and drab brown, yellow, or sometimes green.
To identify the many different kinds of stoneflies, one must use a magnifying lens and note details of mouthparts, wing vein patterns, leg segments, cerci, gills, and more.