(Goetghebuer, 1921)
Body
Medium sized to large larvae. Living larvae reddish. No lateral and ventral tubules (Wiederholm, 1983; Moller Pillot, 1984a).
Head
The head capsule is shining with a length of 380 - 430 µm. The gula is uniform pale. The eyes are rounded, large and close together or fused. Anterior margin of frontal apotome is straight without a subapical pit, but with anterio-lateral lobes on which the S3 is inserted. Labral sclerite 1 absent, sclerite 2 present.
Antenna
The antenna consists of 5 segments [Pol cf. tritum antenna]. Lauterborn organs distally on the second segment. The blade reaches to the middle of the 5th segment. The 2nd segment about 1.5 times the length of the 3d segment. The 3d segment (12 µm) is about as long as the 4th segment.
Mentum
The mentum has 2 median teeth and 7 pairs of lateral teeth. The median teeth are larger than the first lateral teeth and about equal as the 2nd lateral [Pol unc ment]. The ventromental plates are 0.85 x as wide as the mentum.
Labrum
SI is plumose on both sides and labral lamellae a single plate with numerous distal teeth. The pecten epipharyngis with 3 small plates with distal teeth [Pol pecten epiph] The premandible has three teeth.
Mandible
The mandible with a dorsal tooth [Pol g nub mandible], apical tooth dark and 2inner teeth. The pecten mandibularis is present and seta interna with plumose branches.
Differential characteristics
Two median and 7 pairs of lateral teeth on the mentum [Pol g nub mentum 8], with Lauterborn organs on the second segment and shining dorsal headcapsule will separate Polypedilum from all other genera except from Parachironomus which however has a completely different mentum [Parach arc mentum].
Polypedilum cf. tritum can be separated from the other Polypedilum by:
Pale gula, 1st lateral tooth smaller than the 2nd lateral, head length 380 - 430 µm and 2nd antennal 1.5 times as long as the 3d segment.