Chironomus annularius

auctores nec De Geer, 1776

Diagnosis (Confirmed as annularius with Strenzke identified specimens in coll. ZSM.)
Exuviae 8.6-10.4mm long (n=7).
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 100x95-163x163µm (n=5). Frontal setae 45-65µm long (n=4). Thoracic horn much branched, basal ring of horn 170x67-215x90µm. Tracheal patch of horn without an "eye", patch 125x30-167x40µm; 16-20 tracheoles across (n=7), 1.5-2µm in diameter. Thoracic granulation with little difference in size between granules at suture and further laterad (149e.jpg).
Abdomen: Hook row II entire, length of row 0.63x width tergite (n=1); hooks 78-98 (n=5). Armament of tergites II-VI in the form of an undivided, moderately extensive 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 II-VI not so strongly waisted and with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. The point patches increase in extent from tergite II to V, but on VI the patch is more or less reduced. Points of tergites III and IV medially appearing dense: broader, with longer anterior 'tails' which overlap the points of the preceding row. 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. Seta D4 of tergite VI closer to mid-line than seta D3. Sternites III and IV with well-developed lateral shagreen bands. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Conjunctives IV/V and V/VI armed with points or spinulate points. Pleura of segment IV spinulate, spinules 15µm long. Comb of segment VIII on the end of an elongate ventral cuticular mound with (2)3, 4(5) elongate teeth. Lateral taeniae of segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes weakly rounded, usually with only one taeniate dorsal seta. Anal lobe with 106-126 fringe taeniae (n=6); lobes with brown colour posteriorly spreading onto tergite IX.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 197: Chironomini 94 Chironomus of the Text Key.

Holarctic species (?): Widespread in Europe.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Ponds, ditches, water butts.