Cricotopus tremulus

Author: (Linnaeus, 1758)

Diagnosis (in part after Hirvenoja, 1973a - in italics)
Exuviae 3.5-5.0mm long (n=6) (089-2.jpg).
Cephalothorax: Cephalic tubercles absent; frontal setae on praefrons. Thoracic horn 45-128µm long (n=7), smooth and rounded apically, or with a few granules at tip (089f.jpg); ThR 1.8-3.0 (n=5). Thorax with small sparse points.
Abdomen: Length hook row II 0.49, 0.58 of width tergite II (n=3); hooks 74-84 (n=3). Pedes spurii B II small, III vague. Median transverse point band of tergite III extending anteriorly into the 2nd quarter of the tergite. Apical transverse bands of tergites III-V composed of hooks similar to those of hook row II (089g.jpg). Posterior transverse point band of tergite VI usually medially interrupted, the gap bridged by a few scattered points. Point patches absent on tergites VII and VIII. Dorsal setae I-VIII: 5,5,5,5,5,5,5,2; Lateral setae I-VIII; 1,3,3,3,3,3,4,4; Ventral setae I-VIII: 1,4,4,4,4,4,4,1; other lateral setae on VIII almost as strong as lateral seta 4.
Anal segment: Anal lobe ratio 1.3, 1.5 (n=2). Anal lobes without fringe. Anal macrosetae more or less equally strong, length of anal macrosetae 0.22-0.64x length of the anal lobe (n=3).
(Linked adult male: Langton and Pinder, 2003a)

Note: Specimens of C. tremulus can be distinguished from Cricotopus levantinus by their possessing pedes spurii B II and by not having median armament on tergite II.

Species keys out at Page 931: Orthocladiinae 342 Cricotopus of the Text Key.

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

Ecological notes
Montane streams and northern lakes.