Chironomus fraternus

Author: Wülker, 1991

Diagnosis (n=1, material in coll. Wülker)
Exuviae 10.8mm 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 LxB 140x90µm. Frontal setae 50µm long. Thoracic horn much branched; basal ring 188x90µm; tracheal patch 125x35µm; 15 tracheoles across, 2-2.5µm diameter. Tracheal patch of thoracic horn without an "eye". Anterior thorax small granulate; granulation extends as far as the anterior edge of the wing sheath base.
Abdomen: Hook row II entire; hooks 65. Armament of tergites II-VI in the form of an undivided patch of strong points, not strongly waisted and 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. The points in each segment increasing in size posteriorly; the posterior transverse band not successively increasing in extent to tergite VI. Posterior points of tergites III and IV much larger than the median points on the same tergite. Armament of tergite VI continued posteriorly further behind seta D5: 8 points between the seta and the posterior margin of the point patch (102f.jpg). Points of tergite VIII arranged mainly in distinct short rows of two to five. Seta D4 of tergite VI further lateral than seta D3. Sternites III and IV with the lateral bands spreading inwards and only narrowly joined anteriorly. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Pleura of segment IV spinulate, spinules 12µm long. Conjunctives IV/V and V/VI armed with points or spinulate points. Comb of segment VIII with 3 elongate teeth set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Lateral taeniae of segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes weakly rounded, usually with only one taeniate dorsal seta; each anal lobe with 102/110 fringe taeniae.

Species keys out at Page 192: Chironomini 89 Chironomus of the Text Key.

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

Ecological notes
Larvae in moss in shallow stagnant water.