Diamesa lavillei

Author: Serra-Tosio, 1969

Diagnosis (n=2, unless stated otherwise, material in coll. Serra-Tosio)
Exuviae 3.8, 7.5mm long.
Cephalothorax: Frontal setae 183, 260µm long. Thoracic horn 255µm long; ThR 17 (n=1). Precorneal setae 1-3: 50; 175, 235; 150, 200µm long; situated next to the thoracic horn.
Abdomen: Total dorsal teeth II-VIII 56, 56+. Total ventral teeth III-VIII 42, 60+. Shagreen points of tergite III 6, 7.5µm long. Relative length segments IX:VIII:VII = 1.0:0.73/0.7:1.0; relative width segments IX:VIII:VII = 1.0:1.2,1.36:1.4,1.7. Segment VIII 3.0, 2.8 and segment VII 2.5, 2.4 times as wide as long. Lateral setae 1-4: 100, 190; 105, 190; -- 105, 190; 85, 87µm long.
Note: Abdominal segments evenly pale tan to gold with hardly a trace of pattern (the lateral adhesion marks may be a little more intense). Teeth 60µm long, with basal mound 80µm long (031e.jpg). In pale examples tooth row set on a transverse golden-tinged band.
Anal segment: Anal lobe ratio 1.1, 1.4. Each anal lobe with 3 macrosetae; length macrosetae 0.92, 0.8 times lobe length.

Species keys out at Page 579: Diamesinae 55 Diamesa of the Text Key.

Pyrenees; Caucasian mountains and Turkey.
(For more information see module IdentifyIt – file: Other subfamilies).

Ecological notes
Cold torrents and streams above 1,000m in the Pyrenees.