Thienemann, 1935
Body
Small larvae. Body setae are simpel and bifid or plumose. Anterior and posterior parapods separate bearing a ring of claws. Procercus with a subapical spur and the two pairs of anal tubules are as long as the posterior parapods (Wiederholm, 1983).
Head
Antenna
The antenna consists of five segments. Segment 4 is longer than segment 3. The blade is subequal to the flagellum. The lauterborn organs are large (Wiederholm, 1983).
Mentum
The mentum has three median teeth and 4 pairs of lateral teeth. The ventromental plates are weakly developed. The beard is extremely large radiating from the center Parorthocl mentum.
Labrum
The pecten epipharyngis consists of three scales. The SI, the labral lamellae and the premandible are simpel (Wiederholm, 1983)
Mandible
The mandible has an apical tooth and 3 inner teeth. The seta interna is absent (Wiederholm, 1983).
Differential characteristics
The extreme long beard is distinctive for Parorthocladius and Synorthocladius. The mentum with 3 median teeth separates Parorthocladius Parorthocl mentum from Synorthocladius which only has two median teeth Synor semiv mentum 8.
Diversity
European species: 2
Treated species: 0