Chironomus pilicornis

Author: (Fabricius, 1787)

Diagnosis (n=1, egg reared specimen in coll. W. Wülker)
Exuviae 9.0mm long.
Colour: 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 175x150µm (n=8). Frontal setae 35µm long. Thoracic horn much branched; basal ring of horn 165x85µm; tracheal patch 110x37µm; 14 tracheoles across, 2µm diameter. Tracheal patch of thoracic horn without an "eye". Anterior thorax hardly granulate; dense small granulation begins just behind the level of the insertion of the thoracic horn and continues to posterior margin of the wing sheath base, thereafter rapidly evanescing.
Abdomen: Hook row II entire; hooks 77. 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; the points in each segment increasing in size posteriorly. 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. Armament of tergite VI less extensive posteriorly: 6 points between the seta and the posterior margin of the point patch (102e.jpg). Posterior points of tergites III and IV much larger than the median points on the same tergite. Points of tergite VIII arranged mainly in distinct short rows of two to five. Seta D4 of tergite VI further lateral than seta D3. Lateral longitudinal shagreen bands of sternite IV extensive, similar to those on III. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Pleura of segment IV spinulate, spinules 7.5µm long. Conjunctives IV/V and V/VI armed with points or spinulate points. Comb of segment VIII with 1/3 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. Anal lobes usually with only one taeniate dorsal seta; each lobe with 86 fringe taeniae.

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

Holarctic species: widespread in Europe (not Mediterranean).
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes