Chironomus macani

Author: Freeman, 1948

Diagnosis (n=2 unless stated otherwise; Typ. biotope specimens, coll. W. Wülker.)
Exuviae 10.3, 10.5mm long.
Colour: 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 135x135, 150x137µm, with a short (50-75µm) and narrow (30-45µm) apex on a bulbous base (102l.jpg). Frontal setae 55µm long (n=1). Thoracic horn much branched; basal ring of thoracic horn 195x90, 200x90µm. Tracheal patch 140x60, 145x55µm, without an "eye"; 15, 18 tracheoles across; tracheoles 3-4µm across. Thoracic granulation distinct and extensive.
Abdomen: Hook row II entire, length of row 0.45x width tergite (n=1); 69, 76 hooks. Armament of tergites II-VI in the form of an undivided, narrow patch of strong points, 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. Armament of tergites not strongly reduced anteriorly, e.g. on tergite III the points between the anterior adhesion marks still quite sturdy, the point patch appearing cut off anterior to the adhesion marks (102i.jpg). Armament of tergites II-VI with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Shagreen of sternite II extensive complete posteriorly. Sternites III and IV without an anterior transverse band of shagreen and without lateral shagreen, but may have an extensive median shagreen patch. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Conjunctives IV/V and V/VI at most minutely "rough". Pleura smooth. Lateral setae of anterior segments short, e.g. on III shorter than 100µm long. Comb of segment VIII on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment; comb usually with a single apical tooth. Lateral taeniae of segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes weakly rounded. Anal lobe with 132, 136 fringe taeniae (n=2).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 210: Chironomini 107 Chironomus of the Text Key.

Palaearctic species: Britain and Fennoscandia.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes