Macrostomus trombetensis sp. nov.

(Figs 39–44)

Diagnosis. Thorax black except prosternum and part of propleuron yellow. Abdomen including terminalia black with tergite 1 slightly yellow laterally. Male tergite 8 short, without sinus anteriorly and with shallow sinus posteriorly. Epandrium with posterodorsal lobe of epandrium higher than anterodorsal lobe. Anterior cercus with thin process at posterior margin; posterior cercus vertically elongate with one small secondary protuberance. Hypandrium with two uniseriate setae and shallow sinus on posterior margin. Female hind tibia without pinnate setae.

Description. Holotype male. Body not measured (due to detached head); wing length 2.6 mm. Width of frons approximately subequal to anterior ocellus width. Antenna velvety black. Palpus brown. Thorax shiny black with prosternum and part of propleura yellowish. Thoracic setae: 4 dorsocentrals, 4 antepronotals, 2 proepisternals, 2 pairs of scutellars. Legs shiny yellow with apex of hind femur, almost entire hind tibia and all tarsomeres 3–5 black. Hind femur lacking anteroventral setae at distal third. Wing (as in Fig. 56 of M. albicaudatus). Halter light brown, partially white at knob. Abdomen shiny black with tergite 1 slightly yellow laterally. Terminalia similar to M. albicaudatus nov. sp. (Figs 11–14), except anterior cercus (Fig. 40) narrower in dorsal view, cercal bridge (Fig. 40) larger, hypandrium with 2 uniseriated setae and sinuosity less pronounced (Fig. 41).

Female. Thorax with 3–4 dorsocentrals setae. Hind tibia without pinnate setae. Wing (as in Fig. 57 of M. albicaudatus). Terminalia very similar to M. albicaudatus nov. sp. (Figs 15–17), except sternite 8 (Figs 42, 43) with distal lateral projections more acuminate (as seen ventrally) and genital fork (Fig. 44) with genital chamber much more elongated.

Geographical distribution. Brazil (Pará).

Type material. HOLOTYPE ♂: “ BRASIL, Pará, Rio Trombetas, Cruz Alta”; “ 25–28.vii.1992, varredura, João Vidal”; “ Macrostomus trombetensis Holótipo ♂” (red label) (INPA). PARATYPES. BRAZIL. Same data as holotype (2♀ INPA); Rio Mapuera, Cachoeira, Assunção, Malaise, 5–17.vi.1986, Eq. V. Py-Daniel (1♀ INPA).

Holotype condition. Pinned, head and terminalia in glycerin. Left hind leg lost.

Etymology. Named according to the Trombetas River region where the specimens were collected.

Discussion. See under M. albicaudatus sp. nov.