Orthocladius rivinus Kieffer, 1915

Bruno Rossaro & Carlotta Casalegno, 2001, Description of the pupal exuviae of some species belonging to Orthocladius s. str. van der Wulp, 1874 (Diptera: Chironomidae: Orthocladiinae), with a new key to species of West Palaearctic region, Zootaxa 7, pp. 1-20 : 11-12

Orthocladius rivinus Kieffer, 1915

O. rivinus Kieffer, 1915

Orthocladius Pe 3, Langton, 1984: 150 ( Langton 1991: 186; Langton & Cranston 1991)

O. mariellae Rossaro & Prato, 1991 ( Rossaro 1991)

DESCRIPTION. See Langton & Cranston (1991, Fig. 2 a, 4d) and Rossaro & Prato (1991, Fig. 5, 6, 7; sub O. mariellae ). Thoracic horn 400­425 m long, with strong spines from base to apex. Apex appearing pointed or rounded according to mounting position. Pedes spurii B developed. T II­VI with a dark anterior band. Points on T II reduced to a small posterior field. TIII with posterior point band extending laterally than the apical band. The median points somewhat larger than more lateral ones and showing as a more or less circular area within point patch, especially visible on TV­VI. SII­III­(IV) with branched setae. Lateral setae: 3 on segment II­VI, 4 on segment VII and 5 on segment VIII. Anal lobes with small taeniate extensions of cuticle, anal macrosetae gently curved and hooked at tip, 235­250 m long, longer than in O. oblidens . Anal lobes about 440­450 m long, 340­350 m wide.

COMMENTS. A strict relation between O. rivinus and O. oblidens is here emphasised (see also the key to species below). They are well separated by the length and shape of anal macrosetae.

MATERIAL EXAMINED: ITALY: ABRUZZO: Aterno river, Coppito, 1/5//1989, 1 Pex; 11/11/1989, 1 Pex; 26/2/1990, 1 Pex; 13/3/1991, 1 female /Pex/Lex; 8/1/1992, 1 Pex; 5/2/1992, 1 Pex; 2/3/1992, 1 Pex. Vera spring, 13/5//1992, 1 Pex; Zittola stream, 26/5// 1992, 1 Pex.

Figures

FIGURE 2. 2.3 = O. ticinoi: taeniate extensions of cuticle at the tip of anal lobes; 2.4 = O. obumbratus: taeniate extensions of cuticle at the tip of anal lobes; 2.5 = O. marchetti: anal lobes without taeniate extensions of cuticle