Orthocladius olivaceus

Author: (Kieffer, 1911)

Exuviae 4.3-5.0mm long (m=4.6mm, n=10).
Cephalothorax: Thoracic horn 85-135µm long (m=104µm, n=12), elongate oval, smooth or nearly so; ThR 2.8-5.0 (m=3.7, n=8) (074e.jpg). Four dorsocentral setae, the first, third and fourth thick, the second conspicuously thinner.
Abdomen: Hook row of segment II short, less than 0.34x width of segment II, usually of three or more transverse rows of hooks, or absent (its position occupied by a band of anteriorly directed spinules). Shagreen limited in distribution on tergites. Median point patches absent or just indicated on tergite II; present on III-VI(VII). All points in the posterior transverse bands of tergites II and III similar in size (074f.jpg). Posterior transverse band of tergite VIII usually present. Pedes spurii B conspicuous and pleurae moderately spinulate (spinules c. 6µm long) extending from postero-lateral corners to the anterior quarter of at least II-VI.
Anal segment: Anal lobe ratio 1.7-2.2 (m=2.0, n=11). Anal lobes often with additional teeth laterally or apically, fringe absent. Length of anal macrosetae 0.50-0.66x length of the anal lobe (m=0.56, n=9); one of the setae shorter and thinner than the other two (074g.jpg).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 854: Orthocladiinae 265 Orthocladius of the Text Key.

Palaearctic species: widespread in (central) Europe.
(For more information see module IdentifyIt – file: Orthocladiinae).

Ecological notes
Northern and montane lakes and rivers.