Orthocladius trigonolabis

Author: Edwards, 1924

Diagnosis (Material in coll. ZSM)
Exuviae 3.5mm long (n=1)
Cephalothorax: Thoracic horn elongate, conspicuous, less than 200µm long, tapered to apex, with only a very few minute points near apex (072j.jpg). Four dorsocentral setae, the first, third and fourth thick, the second conspicuously thinner.
Abdomen: Hook row II a discrete pad or band of hooks, less than 0.34x width of segment II, usually of three or more transverse rows of hooks. Median point patches of tergites III-V usually completely fused to the posterior band to form a single trapezoidal patch (072i.jpg). Posterior transverse point band on tergite III not extending further laterally than the apical band. No granulation present on tergites and sternites. Pedes spurii B on segment II conspicuous. Forked or branched setae rare and usually confined to the apical sternites.
Anal segment: Anal lobes without fringe and apical teeth; anal macrosetae longer than half the anal lobe length and usually hooked apically.

Species keys out at Page 866: Orthocladiinae 277 Orthocladius of the Text Key.

Holarctic species: Northern (arctic) Scandinavia.
(For more information see module IdentifyIt – file: Orthocladiinae).

Ecological notes
Northern lakes.