Polypedilum tetracrenatum

Author: Hirvenoja, 1962

Exuviae 4.5-5.2mm long (m=4.9mm, n=10).
Cephalothorax: Cephalic tubercles conical, 50-60µm high, length 0.55-0.8x breadth (n=3) (125k.jpg). Frontal setae 70µm long (n=1). Thoracic horn a bush of fine filaments (about 50), 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; ooks 54-67 (n=5). 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 or hooks. 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 5-12 separate golden-yellow teeth (n=5) (125l.jpg). Segment IV without lateral taeniae; V-VIII with well-developed lateral taeniae, no more than three lateral taeniae on V.
Anal segment: Anal lobes with a dorsal seta set towards the inner edge of the lobe; each lobe with 27-38 fringe taeniae (m=33, n=10) in a single row, extending only to the tip of the lobe externally.
Note: Similar to Polypedilum nubifer but smaller and with apical bands present only on III and IV.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 324: Chironomini 221 Polypedilum of the Text Key.

Widespread in Europe, NW Africa.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Shallow standing water.