Plecoptera is an order of insects known as stoneflies. 3,500 species are described worldwide. Stoneflies are found worldwide, except Antarctica. They are believed to be one of the most primitive groups of Neoptera, with close relatives identified from the Carboniferous and Lower Permian geological periods, while true stoneflies are known from fossils only a bit younger.Plecoptera are found in both the Southern and Northern Hemispheres, and the populations are quite distinct, although the evoluti