Nallachius furcatus new species

(Figs. 1a, 2 a–c)

Diagnosis. MP2 vein not fused with CuA vein and Rs vein with four branches in the forewing, males with dorsal lobe of ectoproct well-developed and median lobe with forked apex.

Description. Body length: 2.5mm. Head light brown except for the region just behind the antennae and tubercles, brown. Vertex with anterior tubercle larger than the two posterior tubercles. Antenna 13-segmented; segments 2–12 with long processes (Fig 1a), predominantly light brown, except the slightly lighter brown pedicel and flagellomere junctions.

Pronotum light brown with two brown tubercles anterolaterally, both covered by long setae; two posterolateral tubercles lighter brown. Pterothorax brown with light brown spots on median region. Scutellum brown with light brown lateral margin. Pleuron light brown.

Legs light brown, except brown spots on tibia and apex of femur. Forewing elongate with rounded posterior margin, membrane hyaline with multiple irregular, brown infuscate bands. Few costal crossveins, forked mostly on distal half. Two radial crossveins (R1–Rs) and RS vein with four branches. First MA fork between the level of the first and the second radial crossvein. First MP fork before the level of the MA origin. CuA vein not fused with MP2 vein. Forewing length: 5.2mm. Hindwing similar to forewing except shorter and simple costal crossveins.

Abdominal tergites light brown. Terminalia: ectoproct flattened with dorsal lobes near midline, curving laterally when seen in dorsal view (Fig. 2 a), in lateral view hook shaped; digitiform process elongated with apical spine (Fig. 2 b). Gonocoxites connected posteriorly with gonarcus, slender and lance-shaped at apex, wider at base (Fig. 2 c). Mediuncus lobes spatulate with apices curving medially, almost touching one another, and with subapical, rounded, lateral projections. Median lobe with concave basal margin, apex forked, ending at level of the lateral projections (Fig. 2 c).

Etymology. The specific name is derived from the Latin furcatus (= forked) and refers to the forked apex of the median process of the terminalia.

Material examined. Holotype male, BRAZIL: Paraíba, Cabaceiras (Fazenda Bravo), caatinga de lageiro/ Armadilha luminosa, 28–29.vi.1986, D. S. Amorim. Stevaux. col. Condition: good, terminalia in a microvial with glycerine, pinned along with the specimen.

Comments. Nallachius furcatus is similar to N. dicolor Adams, 1970 and N. ovalis Adams, 1970, both from the state of Santa Catarina and N. phantomellus Adams, 1970, from the state of Mato Grosso do Sul. Each of these has flattened dorsal lobes of the ectoproct, approximately along the midline. Nallachius furcatus can be distinguished from the other three by the Rs vein four branched, (five in the others) and genitalic median lobe with forked apex (simple in the other species, see Adams (1970)).