Medium-sized larvae, up to 7 mm long.
Frontoclypeal apotome present. Head capsule setae simple.
Antenna with 5 segments; segments consecutively shorter, except segment 5 longer than segment 4. Ring organ on basal 1/4 of segment 1. Blade extending to level of segment 3. Lauterborn organs about 1/2 length of segment 3. Style longer than length of segment 3.
Single labral sclerite present. SI plumose; remaining S setae simple. Labral lamellae consisting of 2 apically pectinate lobes. Chaetae serrate; spinulae simple. Pecten epipharyngis consisting of 3 short, smooth scales. Chaetulae laterales simple to serrate; chaetulae basales present. Ungula with basic sclerite. Premandible bifid; brush absent.
Apical tooth shorter than combined width of 4 inner teeth. Seta subdentalis pointed, slightly curved. Seta interna with 7-8 apically plumose branches.
Two median and 6 pairs of lateral teeth present; all teeth subequal in size and shape or median and first lateral teeth broader than remaining lateral teeth and second lateral teeth shorter than first and third lateral teeth. Ventromental plate long; beard well-developed. Setae submenti arising close to mentum.
Maxilla palpiger with simple rounded lamellae. Galea with a few pointed lamellae and without pecten galearis. Setae maxillaris simple.
Body with separate anterior and posterior parapods, each with a group of claws. Procercus longer than wide, bearing 7 anal setae; without spur. Anal tubules shorter than posterior parapods.
Diplocladius presently is considered to be monotypic with the species D. cultriger.
Holarctic in distribution. The larvae are never abundant, being found in cool springs, small flowing and still water bodies.