Thienemann and Harnisch, 1932
Body
Medium sized larvae up to 9.4 mm long. Thorax often with brown transverse stains. The anterior and posterior parapods are separate and bear rows of claws. Procercus usually with a posterior spur and two pairs of anal tubules present (Wiederholm, 1983; Moller Pillot, 1984b).
Head
Antenna
The antenna consists of five segments. The blade is shorter than the flagellum. Lauterborn organs are distinct.
Mentum
The mentum has two median teeth and 5 pairs of lateral teeth. The ventromental plates are large, covering one or more mental teeth. The beard is well developed with numerous setae Rheocricotopus mentum.
Labrum
The pecten epipharyngis consists of three scales, SI is bifid or, rarely with 6-8 apical teeth and the premandible has one apical tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and three inner teeth. The seta interna has simpel or partly plumose branches (Wiederholm, 1983).
Differential characteristics
The bifid SI, large ventromental plates with beard Rheocricotopus mentum and procercus with spur separate Rheocricotopus from all other Orthocladiinae.
Diversity
European species: 7
Treated species: Rheocricotopus atripes
Rheocricotopus chalybeatus
Rheocricotopus effusus
Rheocricotopus fuscipes
Rheocricotopus glabricollis