Stoneflies

Part of speech: noun

Definitions

1. Aquatic insects whose larvae live in clean, fast-flowing streams and whose adults have two pairs of membranous wings held flat over the body
2. Slender winged insects of the order Plecoptera, whose nymphs develop underwater and are often used as indicators of water quality
3. Insects with flattened, aquatic young that cling to stones in rivers, while the winged adults are short-lived and rarely feed

Etymology: "Stoneflies" is the plural of "stonefly," an insect whose name combines two plain English words: "stone" and "fly." The nymphs of these insects live under river stones, which is the likely reason for the first half of the name. The "fly" half refers to the adult insect's two pairs of wings, which fold flat along the back when resting.