Medium-sized larvae, up to 7 mm long.
Antenna as long as mandible; 5 segmented although a vestigial segment 6 might be present; segment 4 much longer than third. Blade extending beyond terminal antennal segment. Lauterborn organs and style present, distinct.
Labrum with SI plumose; SII or SIII reduced to tubercle, the other fine, SIV distinct. Weakly sclerotized labral lamellae present. Chaetae simple. Pecten epipharyngis consisting of 3 rounded scales, remaining chaetulae laterales simple. Premandible simple, with broad inner tooth; brush absent.
Apical tooth shorter than or subequal to combined width of 1-2 inner teeth; mola sclerotized apically, giving the impression of an additional tooth. Seta subdentalis stubby and translucent. Seta interna with 6-7 serrate branches.
Mentum with either 1 broad, simple median tooth or with 2 poorly separated median teeth; with 4 pairs of lateral teeth, outer tooth often apically bifurcate and characteristically curved outward. Ventromental plates weak; without beard.
Maxilla with palp short and squat, with long apical seta. Lamellae on palpiger base small. Galear lamellae translucent and divided into fine spines. Setae maxillaris long and slender. Simple appendix seta present, shorter than setae maxillaris.
Body with anterior parapods fused basally, with simple claws. Posterior parapods long and narrow with few simple claws. Preanal segment curved over anal segment. Procercus short, bearing apically 1 seta up to 1/3 body length; lower lateral seta long. Anal tubules long, medially constricted, extending beyond posterior parapods.
Larval Parachaetocladius live in springs and spring-fed streams in the Holarctic region only.