Hirvenoja, 1973
Body
Medium sized larvae up to 9 mm long. Living larvae light-green or brownish (H. varians). L4 setae are simpel. The anterior and posterior parapods are separate and bear rows of claws Halocl varians claws ant pp. The procercus is present but the anal tubules are absent (Hirvenoja, 1973; Wiederholm, 1983; Moller Pillot, 1984b).
Head
Antenna
The antenna consists of five segments. The blade is shorter than the flagellum. Lauterborn organs are absent or not visible (Hirvenoja, 1973).
Mentum
The mentum has one median tooth and 6 pairs of lateral teeth. In Halocladius s.s. the median tooth is dome shaped Halocl varians mentum, while in H. (Psammocladius) the median tooth is flat or concave Halocl Psammo mentum. The ventromental plates are narrow. The beard is short and indistinct in Halocladius s.s. Halocl stagnorum mentum and very long in H. (Psammocladius) Halocl Psammo mentum (Wiederholm, 1983; Moller Pillot, 1984b).
Labrum
The pecten epipharyngis consists of three scales, SI is plumose and the premandible has 1-2 apical teeth in Halocladius s.s. and 3-5 teeth in H. (Psammocladius) (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and 3 inner teeth. The seta interna has serrate branches (Wiederholm, 1983).
Differential characteristics
In brackish water the combination of missing anal tubules and a mentum with 6 pairs of lateral teeth Halocl varians mentum Halocl Psammo mentum is distinctive for Halocladius s.l.
Diversity
European species: 5
Treated species:
Halocladius braunsi
Halocladius fucicola
Halocladius variabilis
Halocladius varians