Perlodidae

The family Perlodidae is composed of at least 50 genera and over 350 species, with the fossil records extending at least from the Triassic. The majority of perlodid stoneflies are univoltine - one generation occurs per year. Usually, adults emerge from April to June. Many species have an egg diapause during the warmer months; this allows them to inhabit otherwise unfriendly environments like temporary seeps or streams. Larvae have flattened bodies, often with patterns on their heads and thoraces, long tails, and divergent hind wing pads. Unlike the similar common stoneflies, perlodid larvae do not have branching gills on their thoraces. The perlodids are found throughout North America.

The Perlodidae are generally lotic and lentic erosional. These habitats are flowing streams or pools that contain sediments, vascular plants, and detritus. They are most often found in cool, clear streams with rocky bottoms. They are found under rocks and in coarse particulate organic matter where many prey are to be found. The larvae are generally considered to be clingers as can be seen by their wide stance for gripping substrates.

The perlodid larvae are mostly predators that engulf their prey, although a few species are scrapers and collector-gatherers. They will eat a variety of small invertebrates, but they are also known to eat plant matter, especially when young.

These 57 genera belong to the family Perlodidae:[1][2]