Author: Meigen, 1804
Diagnosis
Exuviae 8.1-10.0mm long (m=8.9mm, n=10).
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 95x85-137x107µm (n=8). Frontal setae 33-57µm long (n=9). Thoracic horn much branched; basal ring of horn 133-180 x 63-87µm; tracheal patch 95-135 x 35-45µm (n=10), about 12-14 tracheoles across the anterior lobe; tracheoles 2-2.5µm in diameter. Tracheal patch of thoracic horn without an "eye". Thoracic granulation strong to dorsocentral seta 1 and beyond.
Abdomen: Hook row II entire, length of row 0.51-0.59x width tergite (n=4); hooks 67-94 (n=10). Armament of tergites II-VI in the form of an undivided patch of strong points, the points in each segment increasing in size posteriorly. The point patches increase in extent from tergite II to V, but on VI the patch is more or less reduced. 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 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 of sternite IV reduced to a small median patch or absent. Parasternite II obviously shagreened; III (and often IV) shagreened. Pleura of segment IV extensively armed with relatively large spinules: about 20µm long, 1µm broad at base. Comb of segment VIII with 1-3 (rarely 4-6) stout 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 lobe with 97-158 fringe taeniae (m=129, n=10).
(Linked adult male: Langton and Pinder, 2003a)
Note: Chironomus piger has similar pupae, with all measurements falling within the range of C. riparius.
Species keys out at Page 184: Chironomini 81 Chironomus of the Text Key.
Distribution
Holarctic species: widespread in Europe.
(For more information see module IdentifyIt – file: Chironominae).
Ecological notes
Ponds, ditches.