Larval wings/wing pads absent. Eye spots present, but compound eyes absent. Segmented legs present on thorax. Abdominal segment 9 with either one slender tail or pair of anal prolegs, each with two hooks. Seven or eight pairs of filaments or gills laterally on abdomen, with never more than one pair per segment.
Abdominal segments 1–8 with paired, 2-segemented, lateral filaments. Abdominal segment 10 has pair of 1-segemented filaments. End of abdomen with pair of anal prolegs, each bearing 2 claws. Mature larvae 30–65 mm long.