Author: Hirvenoja, 1973
Diagnosis (Material in coll. ZSM; in part after Hirvenoja, 1973a - in italics)
Exuviae 4.0-5.0mm long (n=6).
Cephalothorax: Cephalic tubercles absent. Frontal setae on frontal apotome. Thoracic horn 78-163µm long, club-shaped with a narrow neck, smooth or with minute spinules apically; ThR 2.6-8.0 (n=7). Precorneal setae not on conspicuous mounds.
Abdomen: Length hook row 0.43, 0.59 of width tergite II (n=2); hooks 47-156 (n=6). Small pedes spurii B present on segment II. Median point patches of tergites III and IV extending laterally nearly as far as the lateral adhesion marks anteriorly, thereafter narrowed rapidly to the outer limit of the anterior adhesion marks and then to the broad fusion with the posterior transverse point band on each side of the posterior adhesion marks, leaving a wide mid-lateral bare patch (087i.jpg). Point patches absent on tergites VII and VIII. Dorsal setae I-VIII: 4,4,4,5,5,5,5,2; Lateral setae I-VIII: 1,3,3,3,3,3,3,4; Ventral setae I-VIII: 1,3-4,4,4,4,4,4,1, lateral seta 4 on VIII not stronger than other lateral setae.
Anal segment: Anal lobe ratio 1.4-1.6 (n=3). Anal lobes without fringe. Length of anal macrosetae 0.50-0.71x length of the anal lobe (n=3).
Species keys out at Page 916: Orthocladiinae 327 Cricotopus of the Text Key.
Note: The pupa of Cricotopus obtusus is according to Hirvenoja (1973) questionably separable from that of arcuatus. He suggests that arcuatus may be separable by its weakly granulate and wrinkled suture; in obtusus this is smooth.
Distribution
N(W) Europe.
(For more information see module IdentifyIt – file: Orthocladiinae).
Ecological notes
Lakes.