Sogana robustocarina sp. nov.

(Figs. 6, 16–18, 22, 27, 40–43, 50, 51)

Description. Length (from apex of vertex to tip of fore wings): ď 10.5 mm, Ψ 10.5 mm.

General color tawny brown. Vertex (Figs. 6, 16–18) with blackish, I-shaped stripes at apex; central disc suffused with blackish, lateral margins black; lateral areas and all carinae on vertex, pronotum and mesonotum yellowish brown. Frons (Fig. 17) with 6 pairs of carmine transverse bands, carinae on frons and clypeus orange to reddish. Gena (Fig. 18) with a black patch. Ocelli (Fig. 18) suffused with red. Legs brown, trochanters fuscous, apex of femora reddish, postfemora with long fuscous stripes.

Vertex (Figs. 6, 16) with anterior margin broadly convex in dorsal view, lateral areas convex and ridged; median carina percurrent and broadly thickened, diverging medially. Fore wings (Fig. 22) with 14–15 apical cells (sometimes the left and right fore wings are different) and 5 subapical cells. Spines of hind legs: hind tibia laterally 3, distally 6, basitarsus distally 6.

Proportions. Vertex with ratio of median length to the widest breadth 1.11:1, frons with ratio of median length to the widest breadth 1.67:1, pronotum with ratio of width to median length 4.22:1, pronotum and mesonotum together medially about 1.4 times as long as median length of vertex, fore wings with ratio of length to maximum breadth 3.31:1.

Male genitalia (Figs. 27, 40–43, 50, 51) with pygofer very narrow and high, wider dorsally than ventrally, with dorsal posterior margin angularly produced posteriorly in lateral view (Fig. 27). Anal tube with apical margin oblique concave in dorsal view (Fig. 40), more or less bent ventrad in lateral view (Fig. 27). Gonostylus (Figs. 27, 42, 43) 3.31 times as long as broad in lateral view. Aedeagus (Figs. 41, 50, 51) with three stout processes: one anterodorsally directed process arising from left side at apical fifth, which is longer than threequarters of aedeagus, reaching approximately to base of aedeagus, with distinctly teeth along margin and a sharp protrusion on basal margin; the other anterodorsally directed process arising from dorsal margin at apical fifth, with 5–8 stout spines on ventral margin; the third process forked basally, arising below the left process on right side and directed posteriorly; endosoma membranous, distinctly expanded, with 2 processes: the dorsal one stubby, the ventral one slender and cuspidal; phallotrema long and narrow, exposed subapically on the left side (Figs. 50, 51); periandrium developed, ventrally protruding into a very short, triangular process at apex.

Material examined. Holotype ď, [MALAYSIA:] British N. Borneo, Kalabakan, Primary forest, 15.XI.1958 (T. C. Maa) (BPBM). Paratypes. [MALAYSIA:] 1ď, British N. Borneo, Keningan, 12–17.I.1959 (T. C. Maa); 1Ψ, British N. Borneo, Kalabakan, Primary forest, 10.XI.1958 (T. C. Maa) (both in BPBM).

Etymology. This new species is named for the presence of a robust median carina on the vertex.

Distribution. Malaysia (Borneo).

Remarks. This species is externally similar to S. stimulata Melichar, 1914 from Mentawei Islands, Indonesia in having the vertex with lateral areas between sublateral carinae and lateral carinae not distinctly depressed (shallowly depressed in S. stimulata; convex in S. robustocarina sp. nov.). It can be distinguished from the latter species by the shape of the median carina of vertex (Figs. 6, 16), pigmentary pattern on vertex (Figs. 6, 16–18), and its distinct aedeagal structure (Figs. 27, 41, 50, 51).