What is Stonefly?
{{Taxobox | name = Stoneflies |fossil_range= [[Permian]] - Recent | image = Eusthenia sp.jpg | image_caption = Adult of [[genus]] ''[[Eusthenia]]'' | regnum = [[Animal]]ia | phylum = [[Arthropod]]a | subphylum = [[Hexapoda]] | classis = [[Insect]]a | subclassis = [[Pterygota]] | infraclassis = [[Neoptera]] | superordo = [[Exopterygota]] | ordo = '''Plecoptera''' | ordo_authority = [[Hermann Burmeister|Burmeister]], 1839 | subdivision_ranks = [[Suborder]]s | subdivision = [[Arctoperlaria]] }} The '''stoneflies''' are an order of [[aquatic]] [[insect]]s called '''Plecoptera'''. There are some 3,500 described species worldwide, and new ones are still being discovered. Although stoneflies are found [[worldwide]], they are absent from [[Antarctica]]. Stoneflies are believed to be one of the most [[primitive]] groups of [[Neoptera]]. Their close [[:wikt:relative|relatives]] are identified from the [[Carboniferous]] and Lower [[Permian]] [[Period (geology)|geological periods]]. True stoneflies, known from [[fossil]]s, are only a little younger. The [[larva]] have [[claw]]s on their [[legs]].<ref name=Randall37>Jason Randall, ''Feeding Time: A Fly Fisher's Guide to What, Where & When Trout Eat'' (Mechanicsburg, PA: Headwater Books/Stackpole Books, 2013), p. 37</ref> This allows them to better hang on to things in their [[environment]] and withstand stronger [[Current (fluid)|current]].<ref name=Randall37/> They need fast moving water in [[stream]]s and [[river]]s to survive. They cannot tolerate the low [[oxygen saturation]] found in warm water. They usually live in cold clean streams with a lot of [[turbulence]] (such as [[rapids]]).<ref name=Randall37/> The adult stoneflies are easily identified by their [[wings]] that fold over their [[abdomen]].<ref name=Randall37/> The ''pteronarcys'' Stoneflies, found only in [[North America]]n waters, live for several years.<ref>Ernest G. Schwiebert, ''Nymphs; Volume II: Stoneflies, Caddisflies, and Other Important Insects Including the Lesser Mayflies'' (Guilford, CT: Lyons