Order:
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).
Family:
Glossae much shorter than the paraglossae. Multi-branched, filamentous gills present laterally and ventrally on thorax, but not on abdomen.