Chironomus sororius

Author: Wülker, 1973

Diagnosis (n=1, material in coll. Wülker)
Exuviae 10.1mm long.
Colour: Exuviae golden-brown to dark brown. Contrast in colour between thorax and abdomen not so strongly marked: specimens dark anteriorly also have the abdomen infuscated; outer margin of the anal lobes coloured except at base.
Cephalothorax: Cephalic tubercles conical, LxB 135x95µm. Basal ring of thoracic horn 185x80µm; tracheal patch 145x35µm. Tracheolar patch of thoracic horn without an "eye". Thorax more extensively granulate, without large granules near suture anteriorly; medially (between dorsocentral setae 1 and 2 and the anterior edge of the wing sheath) very distinctly small granulate right up to the suture.
Abdomen: Hook row II entire, length of row 0.48x width tergite; hooks 88. Armament of tergites reduced, e.g. on tergite III extending laterally at most only as far as the inner edge of the lateral of the anterior adhesion marks and setae D4. Posterior points of tergites III and IV little larger than the median points on the same tergite. Armament of tergites II-VI not strongly waisted and with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Parasternite II obviously shagreened. Pleura of segment IV spinulate. Comb of segment VIII with 3 teeth, set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Segment VIII with 5 lateral taeniae.
Anal segment: Anal lobe with 108/112 fringe taeniae and with two broad-taeniate dorsal setae arising quite close together in the anterior third of the lobe.

Species keys out at Page 190: Chironomini 87 Chironomus of the Text Key.

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

Ecological notes
Alpine pools.