Common Stoneflies

The Perlidae are a family of stoneflies, with more than 50 genera and 1,100 described species. The majority of the Perlidae are found in eastern North America, but they occur worldwide except for Antarctica and parts of Africa. Their lifecycles range between one and three years. The adults emerge in the summer; they are very active and known to be attracted to light sources. They are usually very sensitive to changes in environment.

Perlidae are usually lotic and lentic erosional. They are found in cool, clear medium-sized to large streams and sometimes in larger, warm rivers that carry silt. They are crawlers and can move quickly. In still water, no water moves over their gills, so they move their bodies up and down to keep oxygen flowing over them.