Wings developing in wing pads. Mouthparts suitable for chewing. Gills digitiform and located near mouthparts, on neck, sides of thorax, or underside of base of abdomen, never on top or sides of abdomen. Two tarsal claws per leg. Only two tails (cerci).
Paraglossae and glossae about same length. Second tarsal segment of each leg about same length as first. Wing pads divergent, not parallel with body. Gills absent on abdominal segments. Unlike Peltoperlidae, gills, if present, not conical, and thoracic sterna not overlapping. Unlike Nemouridae, hind legs not reaching end of the abdomen.