Cricotopus trifasciatus

Author: (Meigen, 1813)

Diagnosis (in part after Hirvenoja, 1973a - in italics)
Exuviae 4.8-6.2mm long (m=5.5mm, n=21).
Cephalothorax: Frontal setae on frontal apotome, 170-315µm long (m=211µm, n=9), 3-4µm thick. Thoracic horn 125-235µm long (m=179µm, n=20), smooth, without a narrow basal stalk; ThR 5.1-10.8 (m=8.1, n=13). Dorsocentral seta 2 distinctly thinner than 1; setae 3 and 4 equal or subequal, usually shorter than seta 1 and/or 2. Thorax strongly granulate, obvious granulation reaching the precorneal setae; precorneal setae not on conspicuous mounds (085h.jpg).
Abdomen: Length hook row 0.36-0.55x width tergite II (m=0.47, n=10); hooks 94-155 (m=128, n=10) in 3-4 rows. Pedes spurii B absent or only vaguely indicated on II. Strong shagreen on tergites II-VI, uniformly distributed between lateral adhesion marks, only anterior transverse band nearly as wide as tergite. Point patches absent on tergites VII and VIII. Dorsal setae I-VIII: 3-4,4,4,5,5,5,5,2; Lateral setae I-VIII: 1,3,3,3,3,3,3-4,4; Ventral seate I-VIII: 1,4-5,4-5,4-5,4-5,4-5,4-5,1-2; lateral seta 4 on VIII similar to or weaker than the other lateral setae; lateral seta 4 on VII usually very small or absent.
Anal segment: Anal lobe ratio 1.6-2.1 (m=1.8, n=12). Anal lobes without fringe. Length of anal macrosetae 0.34-0.48 length of the anal lobe (m=0.44, n=13).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 908: Orthocladiinae 319 Cricotopus of the Text Key.

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

Ecological notes
Stagnant and flowing water.