Perlidae

April to August

Korea, Russian Far East and Europe

It is around 25~30-millimeter-long. They usually have brown or dark brown body with black head and thorax. Wings are yellowish brown, and the end of femur and tarsus are black. It also used to be called ‘yellow-legged stone flies (oyamia coreana)’ because of the color of its legs. Larvae have tracheal gill in rectum at the end of abdomen, which makes it distinguishable from other stone flies.

They easily observed in Korea and usually inhabit in the upper and middle reaches of the river.