Chironomus nudiventris

Author: Ryser, Scholl and Wülker, 1983

Exuviae 9.2-12.6mm long (m=10.8mm, n=10). (Southern (south France and Spain) specimens tend to be smaller than northern (Belgium).)
Colour: Exuviae golden to golden-brown. (The pupa is very similar to that of Chironomus bernensis, but is generally larger and darker in colour. It also resembles Ch. (Camptochironomus) pallidivittatus, but pallidivittatus has extensively granulate thorax.)
Cephalothorax: Cephalic tubercles LxB 145x120-210x175µm (n=8). Frontal setae 54-80µm long (n=6). Basal ring of thoracic horn 150x72-240x120µm; tracheolar patch 112x25-185x56µm (n=8); 19-24 tracheoles across (n=3); 2.2-2.8µm diameter. Tracheolar patch of thoracic horn without an "eye". Thorax more or less smooth.
Abdomen: Hook row II entire, length of row 0.55-0.7x width tergite (n=4); 94-146 hooks (n=6). 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. Sternite I with a triangular patch of small points postero-laterally. Shagreen of sternites III and IV forming a lateral longitudinal band on each side, which may spread inwards anteriorly. Comb of segment VIII brown, with 5-9 elongate teeth (but tips frequently broken off (n=9), set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment.
Anal segment: Anal lobe with 98-199 fringe taeniae (n=8); lobes brown with margin transparent for a great part of their length.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 159: Chironomini 56 Chironomus of the Text Key.

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

Ecological notes
Large rivers, canal, slow flowing streams.