(Walker, 1856)
Subgenus Allopsectrocladius
Body
Large larvae up to 15 mm long. The purple trachea are distinct. The anterior and posterior parapods are separate and bear rows of claws. Procercus brown sclerotized with 2 large spurs Psec platypus procercus9 and two pairs of anal tubules present. The claws on the posterior parapods are brown (Wiederholm, 1983; Moller Pillot, 1984b).
Head
The head length is 0.68-0.92 mm (Moller Pillot, 1984b).
Antenna
The antenna consists of five segments. The blade is shorter than the flagellum. Lauterborn organs are small or absent.
Mentum
The mentum is flattened with indistinct teeth and the lateral sides strongly bend inwards. The ventromental plates are large covering some lateral teeth. The beard is distinct.
Labrum
The pecten epipharyngis consists of three subequal spined scales, SI is palmate Psec barbimanus S1 and the premandible has one apical tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth which is about 2.5 x the combined inner teeth. The tip is black and the basal part of the apical tooth is pale Psec platypus mandible9. The seta interna absent (Wiederholm, 1983; Moller Pillot, 1984b).
Differential characteristics
The combination the palmate SI Psec barbimanus S1 on the labrum, beard present and procercus with spurs Psec psilopterus procercus9 is distinctive for the genus Psectrocladius.
P. obvius agg can be separated from all other Psectrocladius by the distinct trachea and the head length 0.68 mm.