(Meigen, 1830)
Body
Medium sized larvae up to 7 mm long. Freshly preserved larvae (ethanol) have a thorax spotted with purple-blue stains and a blue-green abdomen. After a long time (18 years) of preservation (70% ethanol) the thorax may still have large brownish stains. The abdomen can turned light brown. The L4 on the abdomen is short and simpel. The anterior and posterior parapods are separate and bear rows of claws. Procercus and two pairs of anal tubules present (Wiederholm, 1983; Moller Pillot, 1984b).
Head
The head length is 0.35 - 0.40 mm (Moller Pillot, 1984b).
Antenna
The antenna consists of five segments. The blade is shorter than the flagellum. Lauterborn organs are conspicuous.
Mentum
The mentum has one median tooth and 6 pairs of lateral teeth. The first lateral widens from the base to the middle of the tooth. The ventromental plates are weak. The beard is absent Paratrich ruf mentum.
Labrum
The pecten epipharyngis consists of three scales, SI is bifid and the premandible with one apical tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and 3 inner teeth. At the base of the ssd there is a lobed ring, seen only at magnification of 400 x or more Paratrich ruf mandible 8.
Differential characteristics
The stained abdomen helps separating Paratrichocladius from Cricotopus and Orthocladius. With both genera it shares the amount and distribution of the mentum teeth, weak ventromental plates, bifid SI, 5 segmented antenna and mandible with three inner teeth. From most Cricotopus species Paratrichocladius can be identified by the simpel L4 setae. From Orthocladius it can be separated by the lobed ring at the base of the ssd Paratrich ruf mandible 8.