Chironomus pe33

new form

(A species with pupal exuviae exceedingly like that of Chironomus Pe35 but adult hypopygium of the riparius type.)
Exuviae 6.6-10.0mm long (n=6).
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 conical, LxB 86x80-140x100µm (n=6). Frontal setae 30-46µm long (n=6). Basal ring of thoracic horn 104x60-184x88µm (n=5); tracheal patch 80x24-108x40µm (n=4); 9, 10 tracheoles across; 3, 3.5µm in diameter. Tracheolar patch of thoracic horn without an "eye". Thorax more extensively granulate, without large granules near suture anteriorly; medially (between dorsocentral setae 1 and 2 and the anterior edge of the wing sheath) very distinctly small granulate right up to the suture.
Abdomen: Hook row II entire, length of row 0.45-0.58x width tergite (n=3); hooks 56-101 (n=5). 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. Armament of tergites II-VI not so strongly waisted and with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Posterior points of tergites III and IV much larger than the median points on the same tergite. Points of tergite VIII mainly isolated and irregularly arranged. Shagreen of sternite II continuous from postero-lateral corner to seta V5, the region between containing points of similar size to those on each side. Lateral longitudinal shagreen bands present on sternite III, but not on IV. Parasternite II obviously shagreened. Pleura of segment IV spinulate, spinules 12µm long. Comb of segment VIII with 1-4 robust apiculate teeth, set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Lateral taeniae on segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes usually with only one taeniate dorsal seta; each lobe with 61-132 fringe taeniae (n=6).

Form keys out at Page 194: Chironomini 91 Chironomus of the Text Key.

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

Ecological notes
Widely distributed: ponds, rice fields.