Polypedilum bicrenatum

Author: Kieffer, 1921

Exuviae 4.6-5.4mm long (n=8).
Cephalothorax: Cephalic tubercles rounded or rounded-conical (125m.jpg). Frontal setae 130µm long (n=1). Thoracic horn of about 8 broad filaments, filaments much shorter than half the length of the abdomen. Thorax with conspicuously large granules near suture (112b.jpg).
Abdomen: Hook row of segment II without an additional patch of small points or hooks at each end; hooks 48-68 (n=8). Tergites II-VI with obvious anterior transverse bands of points stronger than those of the median patch. Armament of tergites II-V continuous: an anterior transverse band of points joined broadly to the postero-median trapezoidal or rectangular marmorate patch of smaller points. Tergites III and IV armed with an apical band of points, points of the apical bands as strong as those of the median point patch. Median points of tergites II and III obviously smaller than those of the anterior band, which is distinct. Tergite VII without trace of a median point patch. Sternite I without two antero-lateral armed humps. Pedes spurii B II well-developed. Conjunctives with points no larger than those of the anterior transverse bands of the tergites. Vortex present. Comb of segment VIII of 1-7 teeth (n=8), comb in the form of strong teeth spreading forwards laterally from the postero-lateral corner (125n.jpg). Segment IV without lateral taeniae; V-VIII with well-developed lateral taeniae, no more than three lateral taeniae on V.
Anal segment: Fringe of anal lobe with 26-33 taeniae (n=8) in a single row extending only to the tip of the lobe externally; with a dorsal seta set towards the inner edge of the lobe.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 325: Chironomini 222 Polypedilum of the Text Key.

Palaearctic species: widespread in Europe, north Africa.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Northern and montane lakes.