Atrichopogon nukini Felippe-Bauer, sp.nov.

(Figs.1; 2 A–J; 3 A–C)

Diagnosis. Male: Only extant species of Atrichopogon with pigmented wings in the Neotropical Region with single gonostylus forked near its midlength, with inner portion longer than outer. Female: Only extant species of Atrichopogon in the Neotropical Region with two distinct darker spots in the wing, uniform color pattern of the antenna and legs, one small ovoid sclerotized spermatheca with short and broad neck.

Male. Head (Fig. 2A): Pale brown. Head width/mouthpart length 2.3. Ommatidia with interfacet pubescence; broadly abutting medially for length of 4.5 ommatidia (Fig. 2B). Antenna pale brown; flagellomeres 2–10 fused; plume on flagellomeres 1–9 well-developed; flagellomeres 10–13 not fused, without plume setae; flagellomere 9 = 0.88 x shorter than flagellomere 10; flagellomere 13 with apical projection not basally constricted; AR 0.98. Palpus pale brown; third segment short, swollen at midlength, with well-developed deep pit at midlength; segments 4, 5 separate, segment 5 conical; PR 1.8.

Thorax: Dark brown. Scutum with setae arising directly from surface; with lateral suture. Paratergite with one seta. Anepisternum not visible in slide mounted specimen. Wing (Fig. 2C) with patch of pigmentation in area of rm and posterior to apex of R 3; macrotrichiae in apical portion of r 3 and m 1; wing length 0.95 mm; CR 0.69. Halter stem pale brown; knob pale. Legs (Fig. 2D) pale brown; hind tibial spur longer than width of hind tibia; empodia present.

Abdomen: Segments 1–8 yellowish brown, with ventrolateral black marks on segments 1–3, 5–6; segments 9, 10 brown. Terminalia brown (Fig. 3A, B): segment 9 equal in width to segment 8; tergite 9 extending to about level of apex of gonocoxite; posterior margin with small medial lobe bearing two setae. Sternite 9 with ventral surface slightly convex, posterior margin nearly straight, with scattered transverse row of 12 median, thin setae. Gonocoxite length 2.7 times basal width, without medial lobe, gonocoxal apodeme truncate. Gonostylus forked near midlength, inner portion elongate, apically curved directed mesally, longer than outer portion; basal 1/3 of outer portion with scattered bristles. Aedeagal-parameral complex (Figs. 3C, D) quadrangular, dorsal portion esclerotized laterally, bearing four projections, two large anteroposterioly directed, two small laterally directed; apical potion, triangular, well sclerotized; lateral arms sclerotized, slightly curved dorsoposteriorly. Cercus elongate, slightly tapering, apex pointed, extending beyond margin of tergite 9.

Female (Fig.2E). Similar to male, with following differences. Head (Fig. 2G): Head width/mouthpart length 2.2–2.9 (2.5, n=5); eyes broadly abutting medially for length of 4.2–5.0 (4.5, n=5) ommatidia. Antenna pale brown, flagellomeres 1–8 elongate, vasiform, AR 1.46–1.57 (1.52, n=5). PR 2.0–2.2 (2.1, n=5). Wing (Fig. 2F) pattern of pigmented membrane as for male; macrotrichia on membrane in apical portion of r 3, m 1 and in apical ½ of M 1; wing length 1.02–1.10 (1.06, n=5) mm. CR 0.71–0.74 (0.72, n=5). Legs as in Fig. 2H. Abdomen yellowish brown (Fig. 2I): Ventrolateral black marks on segments 1–6, well developed on segments 1–3, 5–6, smaller on segment 4; segments 8–10 pale brown; cercus yellowish brown. Genitalia (Fig. 2J): one dark brown ovoid spermatheca, round in some specimens, with very short and broad neck, measuring 77–108 (88, n=5) x 73 –85 (77, n=5) µm.

Types. Holotype male, on microscope slide labeled “ Parque Nacional da Serra do Divisor (7°27’07” S; 73°47’06” W), Acre, BRASIL, 14–15.XI.1996, malaise trap, dense forest, Igarapé Ramón, E.F. Morato col.” (INPA) . Paratypes 5 females, same data as holotype (3 INPA; 2 CCER) .

Etymology. This species is named in honor of the Nukini Indians, inhabitants near the type locality in the Amazon Region.