Definition of "stonefly" []

• Any of numerous weak-flying insects of the order Plecoptera, whose flat, elongated nymphs live under stones along the banks of streams. Adult and larval stoneflies are used as fishing bait. Also called plecopteran. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Nymph: A size 10 or 12 black stonefly is standard, but Hare's Ears and others work."
• "The Nant Fawr Stream that threads through the site provides a haven for further insects such as mayfly and stonefly and also a home to brown trout, eels and even the odd otter."
• "I also found that a tan stonefly nymph with a bead head will make bream go crazy."