Kieffer in Potthast, 1915
Body
Medium sized larvae up to 6.5 mm long. Living larvae are red. Body setae L4 are tufts on the abdomen. The anterior and posterior parapods are separate and bear rows of claws. The procercus is present (Wiederholm, 1983).
Head
The headcapsule with a heavy sclerotized projection next to the antennal base (Wiederholm, 1983).
Antenna
The antenna consists of five segments. The blade is subequal to the flagellum. Lauterborn organs are very large.
Mentum
The mentum is black with an enormous median teeth and 2 pairs of indistinct lateral teeth. The ventromental plates are weak. The beard is absent Symp mentum.
Labrum
The pecten epipharyngis consists of three broad scales, SI is simpel and the premandible has one apical tooth and a broad inner tooth (Wiederholm, 1983).
Mandible
The mandible has an apical tooth and 3 inner teeth. The seta interna has finely serrate branches (Wiederholm, 1983).
Differential characteristics
The mentum with the enormous middle tooth and only two indistinct pairs of lateral teeth is distinctive Symp mentum.