The larvae are light brown with a covering of tiny dark brown microspines. The thorax has three pairs of legs and each segment is covered by a tough, dark-coloured dorsal plate. The first eight abdominal segments have lateral tactile filaments and the first seven have tracheal gills in tufts. The larvae also have spiracles allowing them to breathe on land as well as in the water. At the tip of the abdomen there are two prolegs, each with a dorsal filament and a pair of terminal hooks which enables the larva to anchor itself in fast-flowing water. The mandibles are sclerotised and powerful.