Polypedilum pe9

Form described by Langton, 1991

Diagnosis (n=2)
Exuviae 3.8mm long.
Cephalothorax: Cephalic tubercles very shallow mounds. Frontal setae 45, 90µm long. Thoracic horn of few (about 10) strongly toothed branches; branches much shorter than half the length of the abdomen. Thorax with conspicuously large granules near suture (112b.jpg).
Abdomen: Hook row II short, length of row 0.34, 0.39x width tergite; hooks 27, 28. Tergites II-VI nearly covered with points, which are a little larger medially (124f.jpg); on V and VI there is a progressive reduction in the size of the points. Tergites II-VI with obvious anterior transverse bands of points stronger than those of the median patch with which they may be confluent for the tergite width. Armament of tergite VII medially interrupted. Apical point bands III and IV widely broken medially. Sternite I without two antero-lateral armed humps. Pedes spurii B II well-developed. Vortex present. Comb of segment VIII a strong apical tooth with 1-3 strong lateral and 1-2 minute internal teeth. Lateral taeniae IV-VIII: 2,3,4,4,4.
Anal segment: Anal lobes each with 2 dorsal setae and 34-36 fringe taeniae.
Note: In many respects this form does not resemble a Polypedilum, but the comb of strong teeth spreading anteriorly along the lateral margin of segment VIII (124g.jpg), the shallow, rounded cephalic tubercles with frontal setae and the presence of dorsal setae on the anal lobes suggests Tripodura.

Form keys out at Page 303: Chironomini 200 Polypedilum of the Text Key.

(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Fast flowing stream.