Chaetocnemistoptera pityropyga, sp. nov.

(Figs 8, 29, 39–40, 63–66)

Diagnosis (male). Hind femur without lobes or well defined groups of setulae; hypandrium with lateral row of rounded protuberances.

Material examined. Holotype, ♂, ARGENTINA: Misiones: Reserva Vida Silvestre Urugua-í, 25.97ºS 54.11ºW, 10–12.xii.2003, Malaise trap, 400m, B. Brown & G. Kung col. (LACM). Paratypes: ARGENTINA: 1♂, same data as holotype; 1♂, same data but 2–7.xii.2003; 2♂, Misiones Loreto: Ruinas Jesuiticas, 27.32ºS 55.53ºW, 23.viii.2000, pan trap, P. Fidalgo col. (LACM); 1♂, same data but 27.77ºS 57.28ºW, 24.viii.2000; ECUADOR: 1♂, Sucumbios: Sacha Lodge, 0.5ºS 75.5ºW, 27.viii–10.ix.1994, Malaise trap, 270m, P. Hibbs col. (LACM); 2♂, BRAZIL: Santa Catarina: São Bento do Sul: Malaise trap (no additional data) (MZSP); 1♂, Paraná: Morretes: Parque Estadual do Pau Oco, 25º34’27.9’’S 48º53’46.7’’W, 7–10.iv.2002, M.T. Tavares & team col. (MZSP). Additional material: COLOMBIA: 1♂, Amazonas: Amacayacu NP, 3.82ºS 70.26ºW, 3–5.ix.1997, Malaise trap, M. Sharkey col. (LACM).

Description. Male. Body length, 2.1–2.2 mm. Head. Frons yellow in the ventral half, progressively brown in the dorsal half, pubescent, without median furrow. Ventral fronto-orbital setae close to the eye margin, ventral interfrontal setae about midway between eye margin and frons midline. Flagellomere 1 light brown, pubescent, oval. Arista pre-apical, pubescent. Palpus yellowish-brown. Thorax. Scutum and pleural regions yellowish brown (Fig. 8); anepisternum dorsally setulose; scutellum brown with median and posterior region yellowish-brown. Legs yellowish-brown, hind femur brown at apex. Foretibia with one dorsal seta at basal quarter and anterodorsal row of strong setae. Midtibia with two basal transverse combs of setae, one anterodorsal and two posterodorsal setae and 2–4 small posterodorsal setae between the two large ones. Hind femur swollen (height/length ratio: 0.48) (Fig. 39– 40). Hind tibia with one anterodorsal and 4–6 posterodorsal setae and 13 transversal combs of setae. Wing. (Fig. 29) Costa 0.4 of the wing length, R2+3 vestigial, other characteristics as described for the genus. Halter yellowishbrown. Abdomen. Tergites dark brown. T1–T5 with yellow median and posterior regions. Hypopygium yellowishbrown (Figs. 63–66). Left epandrial process large, ventrally concave, with two apical lobes with sclerotized points and subepandrial apically setose process. Right epandrial margin ventral part projected posteriorly. Hypandrium bilobed, laterally microtrichose and with row of rounded protuberances. Hypoproct with two setae.

Female. Unknown.

Geographic distribution. South of Brazil, north of Argentina and Ecuador (Fig. 72).

Etymology. The specific epithet pityropyga refers to the species rounded protuberances in the hypandrium and is derived from the Greek roots pityron (scales) and pyge (rump, buttocks).