Orthocladius rivulorum

Author: Kieffer, 1909

Diagnosis (in part after Soponis, 1990a - in italics)
Exuviae 3.0-4.5mm long (n=7) (073-1.jpg).
Cephalothorax: Frontal warts weak or absent; cephalic tubercles absent. Antennal sheath base without a sharp tooth. Thoracic horn elongate and closely granulate for its distal three-quarters (073b.jpg), horn 195-265µm long (n=8); ThR 4.4-10.5 (n=8). Precorneals spaced evenly, 2-3x as long as dorsocentrals. 2 Median antepronotals, 0 lateral antepronotals. Four dorsocentral setae, more or less equidistant, the second thinner than the other three. 4-5 Dorsocentrals, weak but often with large sockets; spacing variable (1-1-1-1, 1-1-2, 2-1-1, 2-2). Thorax dorsally smooth with some sculpturing and/or rugosity mesad of wing base and posteriorly along eclosion line.
Abdomen: Tergite I bare; II-V with median patch of recurved hooklets along posterior margin; III-VII with small anterior circular patch of posteriorly-directed points; on VIII a patch is indicated; IV-VI with strong spines in horizontal patch on either side of medial patch; anterior point patch on II-VIII, most extensive on VI-VIII. Tergites III-VII(VIII) with a conspicuous median anterior patch of brown points about one eighth tergite breadth (073-1.jpg , 073c.jpg). Sternites I and VIII bare; II-II with central point patch anteriorly; IV and VII with points anteriorly; VIII with 2 off-center point patches anteriorly. Pedes spurii B present on II, pedes spurii A absent. Dorsal setae I-VIII: 3,5,5,5,5,5,5,2; Ventral setae I-VIII: 2,2,3,3,3,3,3,1; Lateral setae I-VIII: 1,3,3,3,3,3,3,4; Od setae I-VIII: 0,1,1,0,1,0,1,0.
Anal segment: Anal lobe ratio 1.5-1.8 (n=5). Anal lobe strongly developed into large, circular lobes; setae absent. Genital sheaths slightly extended beyond lobe in male, not in female.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 841: Orthocladiinae 252 Orthocladius of the Text Key.

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

Ecological notes