Small to medium-sized larvae, up to 6 mm long.
Antenna scarcely longer than 1/2 length of mandible; 5 segmented; segment 4 longer than third. Blade as long as, or slightly longer than flagellum. Lauterborn organs present, weak. Style well developed.
Most adequately described species have serrate SI with branches often reduced, such that SI is virtually simple, other S setae simple. Chaeta media conspicuous, with several fine branches; labral rod often conspicuous; only 1-2 spinules. labral lamellae absent but comb of 8-18 spines lies below tormal bar. Pecten epipharyngis and chaetulae laterales consisting of simple scales, not always separable; one chaetula often with long teeth. Premandible with 2 apical and 2 more or less distinct inner teeth, with short to distinctive brush.
Apical tooth shorter than combined width of 3 inner teeth. Seta subdentalis relatively long and narrow. Seta interna with 5-6 finely serrate/plumose branches.
Mentum with 2 median teeth as high or higher than the first pair of lateral teeth; 5 pairs of lateral teeth present. Ventromental plate narrow anteriorly, widened and sclerotised posteriorly into rounded tooth-like extension towards, or beyond outer margin of basal mentum. Beard absent.
Maxilla palp normally developed. Galear lamellae absent. Setae maxillaris (always?) simple; pecten galearis absent; anterior lacinial chaeta broad and conspicuous.
Body with anterior and posterior parapods divided, bearing claws. Procercus usually higher than wide, bearing 6-7 anal setae. Anal tubules of varying lengths, usually shorter than posterior parapods. Variably developed body setae, usually simple, rarely bifid.
Limnophyes larvae are found in many habitats, from wave-swept shores of lakes in the meniscus/hygropetric zone, to seepages and mossy banks, to essentially terrestrial locations. The genus is most speciose in the Holarctic, with records from the Afrotropical, Neotropics, Oriental and Australian region associated with fewer species, and generally lacking biological information on larval preferences. Pupal exuvial evidence from Australia confirms the presence of at least one species, in contrast to some previous statements.