Chironomus bernensis

Author: Klötzli, 1973

Diagnosis (Specimens from type locality in coll. W. Wülker.)
Exuviae 8.0-10.6mm long (n=4).
Colour: Exuviae golden-brown to 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 137x117-187x187µm (n=4). Frontal setae 50-63µm long (n=3). Thoracic horn much branched, basal ring of thoracic horn 133x65-200x80µm. Tracheal patch of thoracic horn without an "eye", patch 87x27-150x35µm; 10-18 tracheoles across (n=4); 1-1.5µm in diameter. Thoracic granulation distinct only anteriorly; larger granules here present near suture.
Abdomen: Hook row II entire; hooks 90-143 (n=4). Armament of tergites less 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 in the form of an undivided patch of strong points, point patches increase in extent from tergite II to V, but on VI the patch is more or less reduced. The points in each segment increasing in size posteriorly. The posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Points of tergites III-VI gradually larger over posterior half of tergite. Sternite III without a complete anterior transverse band of shagreen, but with lateral longitudinal shagreen bands which spread inwards anteriorly, but not meet medially. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Pleura IV spinulate, spinules 7.5µm long. Conjunctives IV/V and V/VI at most minutely "rough". Comb of segment VIII with 2-11 narrow teeth (n=4), on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment (100g.jpg). Lateral taeniae of segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes weakly rounded. Anal lobe with 88-150 fringe taeniae (n=4).

Species keys out at Page 188: Chironomini 85 Chironomus of the Text Key.

Europe, Middle East.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Slack water in rivers, e.g. above weirs; inundated pools by rivers; occasionally lakes.