Small larvae, no more than 3 mm long. Head capsule with surface sculpturing.
Antenna subequal to, or longer than head capsule; 4 segments; segment 3 longer than second; segment 4 minute; segments 2 and 3 frequently darkened. Ring organ distinct with median spine. Blade narrow and weak, shorter than flagellum. Lauterborn organs indistinct or absent.
Labrum all labral setae weak; S setae simple; strongly developed seta arising from socket may be either SII or SI setae. Pecten epipharyngis consisting of 3 spines but with first chaetulae laterales of same size and shape, resembling 5 spines. Two outer chaetulae laterales strongly modified; anterior pair large and serrate. Chaetulae basales apparently absent. Premandible with up to 12 minute teeth and strongly developed but translucent brush.
Apical tooth ending dorsally of line of 4 inner teeth, scarcely longer than any of inner teeth. Seta subdentalis absent. Seta interna apparently absent in some species, translucent in others.
Triangular-shaped with either 2 or 3 median teeth and 5 pairs of lateral teeth. Ventromental plate weak; beard absent.
Maxilla small and difficult to interpret. Palp with normal sensillae. Setae maxillaris numerous and apparently all simple. Dorsal side of palpiger with group of fine translucent setae resembling seta interna of overlying mandible.
Body with 2 thoracic segments; meso- and metathoracic segments fused. Anterior parapods elongate, longer than usual in Orthocladiinae. Posterior parapods also elongate, both parapods bearing claws. Procercus small, bearing 4 apical setae. Anal tubules shorter than posterior parapods, tapering to point. Variably developed seta arising from ventral basal side of posterior parapod, this seta is usually plumose, sometimes dark brown and may be up to half the length of posterior parapod.
Corynoneura is a speciose, worldwide-distributed genus. Larvae occur in most aquatic water bodies, standing and flowing, cold to warm. Mouthpart anatomy suggest they may be microfilterers.