Chironomus pe23

new form

Diagnosis (Coll. X.-F. Garcia)
Exuviae 7.3, 8.0mm long (n=2).
Colour: Colour strongly contrasted: cephalothorax dark brown, abdomen colourless with restricted brownish or golden markings; outer margin of anal lobe colourless for most of its length (in pale individuals the contrast is not quite so evident, but the distinction still holds; almost colourless specimens are very similar in appearance to Chironomus bernensis but the extensive granulation of the thorax enables recognition).
Cephalothorax: Cephalic tubercles LxB 120x80, 170x120µm (n=2). Frontal setae 50, 56µm long (n=2). Basal ring of thoracic horn 155x55-207x80µm; tracheolar patch 107x30-160x43µm (n=7);16, 22 tracheoles across (n=2); 1.5µm in diameter. Tracheolar patch of thoracic horn without an "eye". Thoracic granulation strong and extensive over anterior half.
Abdomen: Hook row II entire, length of row 0.62x width tergite (n=1); hooks c.100 (n=1). 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. Shagreen of sternites III and IV forming a longitudinal band on each side. Conjunctive V/VI smooth. Pleura IV densely spinulate. Comb of segment VIII with 2, 3 short apiculate teeth (n=2), 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: 4,4,4,4/5.
Anal segment: Anal lobe with 73, 81 fringe taeniae (n=2).

Form keys out at Page 165: Chironomini 62 Chironomus of the Text Key.

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

Ecological notes
R. Loire.