Medium sized, 8+ mm long. Reddish-yellow larvae.
Frontoclypeal apotome without frontal fenestra, separated from labrum by convex anterior margin, remaining labral area fragmentary.
Antenna with 5 segments. Lauterborn organs opposite on apex of 2nd segment, with style. Ring organ in basal 1/4 of segment 1, seta absent. Blade as long as flagellum, accessory blade moderately long.
SI and SII plumose on both sides; SIII short, slender; SIV normally developed. Seta premandibularis simple. Labral lamellae normal. Pecten epipharyngis divided into 3 parts, each platelet distally serrate. Premandible with 3 teeth.
Mandible with all teeth black, Dorsal tooth relatively short, apical tooth and 3 inner teeth, mola proximal to basal inner tooth deeply notched. Pecten mandibularis modestly developed, lamellae distally divided. Seta subdentalis inserted on ventral surface, simple, long, slender. Seta interna inserted on dorsal surface, plumose, multi-branched.
Mentum glossy black, with distinct dorsomentum of 4 anteriorly-projecting median teeth, of which central 2 are lower than outer pair; 6 pairs of lateral teeth on each side, with 1st lower than 2nd, then decreasing in size laterally to small appressed pair of outermost teeth. Ventromental plates medially connected to median mentum, and thus separated medially by width of median section, broad and semi-lunar, with smooth anterior margin; striae continuous. Setae submenti simple.
Lateral and ventral tubules absent.
Larvae of Polypedilum occur in virtually all kinds of still and flowing waters, with exceptions of the arctic and high mountains. Sediments are the preferred substratum. A few species are also found on hard substrata or mining in water plants.
This genus has a worldwide distribution, with several hundred species. The Holarctic fauna includes at least 100 species.