Oecetis knutsoni Flint

Fig. 8

Oecetis knutsoni Flint 1981: 32 (male, original description); Malicky 1983: 264 (distribution); Flint 1991a: 97 (distribution); 1996: 422 (distribution); Botosaneanu 1994: 51 (distribution).

This species is the largest of the genus in this its occurrence area. The length of each forewing is more than 12 mm and bears the typical dark spots at the forks and at the apical ends of the veins. Oecetis knutsoni is commonly collected at light traps in northwestern Argentina in large numbers. In all specimens collected in northwestern Argentina and Bolivia, tergum X is composed of a paired small finger-like process between the preanal appendages and a rounded, membranous lobe above the phallic apparatus. This lobe is almost invisible. In figure 8B, it is illustrated for the first time.

Material examined. ARGENTINA: Jujuy: Parque Nacional Calilegua, Aº Tres Cruces, 28.xii.1997, (IML) ― 1 male; Sierra de Santa Bárbara (lado E), Río Entre El Fuerte y Palma Sola, 16–17.ix.1998, E. Domínguez. C. Molineri & Ubero cols., (IML) ― 1 male; Río Zapla, 24º16´03”S, 65º07´10”W, 31.v.2000, F. Romero, C. Molineri, V. Manzo & C. Nieto cols., (IML) ― 1 male; Ledesma, Río Zora, 23º44´54”S, 64º42´04”W, 8.xi.1006, 411 msnm, C. Molineri col., (IML) ― 9 males; Salta: Dpto Sta Victoria, Río Huaico Grande, 1600 m, 11.xi.2004, P. Rueda Martín col., (IML) ― 3 males; Lipeo, Río Los Naranjos, 22º25´47”S, 64º44´20”W, 1109 m, 13.xi.2004, P. Rueda Martín col., (IML) ― 25 males; BOLIVIA: Tarija: Arce, 22°12´9.2"S, 64°37´36,6"W, Orosa, La Mamora, 1100m, 04.x.2004, Molineri & Manzo, (IML) ― 6 males. La Paz: Río Takesi, Puente Villa, 16°24'14”S, 67°38'31”W, 22.ii.2002, (IML) ― 3 males. Río Solacama, 16.v.2003, (IML) ― 1 male; 19.ix.2003, (IML) ― 2 males. Río Santa–Catalina, 0 2. xi. 2002, (IML) ― 1 male. Río Unduavi, Puente Villa, 16°24'8”S, 67°38'31”W, 22.ii.2002, (IML) ― 10 males. Tributary of Río Unduavi, 16°23'58”S, 67°38'3”W, 21.ii.2002, (CBF-UMSA) ― 1 male. COLOMBIA: Quebrada La Mosca, 1 Km W Guarne, 7.ii.1983, O. S. Flint col., (NMNH) ― 1 male. Distribution. Argentina (new record), Bolivia, Colombia, Guadeloupe, Peru, Venezuela.