Kieffer, 1922
Body
Large larvae up to 16 mm long. Body setae pale and indistinct. The anterior and posterior parapods are separate and bear rows of claws. Procercus is about twice as high as wide with 8 anal setae and 2 subapical. Two pairs of anal tubules present (Wiederholm, 1983).
Head
Antenna
The antenna consists of four segments. First segment long and segments 3 and 4 are small. The blade is subequal to the flagellum. Lauterborn organs are small but distinct.
Mentum
The mentum has one median broad concave tooth and 6 pairs of lateral teeth. The ventromental plates are very large and extending far beyond the lateral teeth. Beard present Monodiamesa mentum.
Labrum
The pecten epipharyngis consists of three broad spines, SI is serrate distally and the 2 labral lamellae are broad and pectinate. The premandible has 1 apical and 1 inner tooth (Wiederholm, 1983) Monodiamesa labrum premand.
Mandible
The mandible has an apical tooth and 2 inner teeth. The seta interna has 5 serrated and 2 smooth setae (Wiederholm, 1983).
Differential characteristics
The very large ventromental plates in combination with 6 pairs of lateral mental teeth are distinctive for Monodiamesa Monodiamesa mentum.
Diversity
European species: 5
Treated species: 0