Kieffer in Kieffer and Thienemann, 1908
Body
Large larvae up to 9 mm long. Living larvae are blood red. The anterior and posterior parapods are separate and bear rows of claws. Procercus well developed and strongly scelotized distally. Two pairs of anal tubules are present (Wiederholm, 1983; Moller Pillot, 1984b).
Head
The head length is 0.45-0.52 mm (Moller Pillot, 1984b).
Antenna
The antenna consists of six segments. The blade is subequal to the flagellum. Lauterborn organs are small but distinct.
Mentum
The mentum has two median teeth lower than the first laterals and 6 pairs of lateral teeth. The ventromental plates are well developed and cover mental teeth. The beard is absent Trissocl brevipalpis mentum.
Labrum
The pecten epipharyngis consists of three spines, SI is plumose and labral lamellae are simpel triangular. The premandible has two apical teeth and an inner tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and 3 inner teeth. The seta interna has smooth to weakly serrated branches (Wiederholm, 1983).
Differential characteristics
The combination of the antenna with 6 segments and the mentum with 6 pairs of lateral teeth are characteristic for Hydrobaenus Hydrob lugubris mentum, Trissocladius and Zalutschia Zalut gr. mucronata mentum. Trissocladius can be separated by the mentum with median teeth lower than the first laterals Trissocl brevipalpis mentum.