Serridiocerus gen. nov.

Type species: Serridiocerus membranaceus sp. nov.

Body robust. Head wider than pronotum. Crown short with median length as long as length next to eyes, shagreen. Face wider than long; lateral frontal sutures present, curved, reaching ocelli; frontoclypeus and anteclypeus elevated, apex of frontoclypeus and base of anteclypeus broad; anteclypeus strongly convex, base wider than apex, surpassing apex of gena; lateral margin of gena concave in middle; lora narrow; ocelli placed closer to eyes than to each other; antenna aristiform, not expanded apically or subapically (Fig. 8 D). Pronotum shagreen, sparsely punctate, with short lateral margin, anterior margin convex, and posterior margin straight. Mesonotum and scutellum as long as pronotum and crown together (Fig. 8 C). Forewing with 4 apical and 2 subapical cells (crossveins absent, r-m1 and m-cu2 present), outer apical cell very large; appendix broad, extending to middle of 3rd apical cell (Fig. 8 B). Fore femur with setae irregularly arranged and short. Fore tibia with several stout setae on apical half of AV and PV. Hind femur with 2+1 apical setae. Hind tibiae chaetotaxy PD 17–18, AD 6, AV 9–10.

Male abdomen with pair of long tergal apodemes almost reaching entire length of sternite 5; sternal apodeme short, less than one segment long (Fig. 16 D).

Male pygofer divided into short dorsal and long ventral section by horizontal membranous cleft; caudal margin with hooklike process (Fig. 16 A). Segment X with elongate, finger-shaped ventrolateral extension. Subgenital plate slender, with short, sparse setae distally (Fig. 16 A). Style foot-shaped, curved dorsally with ventral margin produced; apical half tapering (Fig. 16 G). Connective T-shaped, with medial longitudinal keel (Figs. 16 B–C). Aedeagal lateral margin serrate in apical half, dorsal and ventral apodemes well developed; gonopore on ventral surface (Figs. 16 E–F).

Distribution. Malaysia (Sandakan).

Etymology. The generic name is derived by combining two words Serr -, referring to the lateral serrations of the aedeagus, with Idiocerus, the type genus of the tribe.

Diagnosis. Serridiocerus gen. nov. can be distinguished by its body brown; frontoclypeus and anteclypeus elevated, apex of frontoclypeus and base of anteclypeus broad; lora narrow; lateral frontal sutures curved, reaching corresponding ocelli; forewing with 2 subapical cells, outer apical cell largest; male pygofer with membranous on dorsum and medial and ventral area; style foot-shaped; aedeagal shaft serrate lateral margin, dorsal and ventral apodeme developed; gonopore situated an ventral margin apically.

Remarks. Serridiocerus gen. nov. is distinguishable from other Idiocerinae by the broad anteclypeus, the laterally serrate aedeagal shaft and presence of a ventral aedeagal apodeme. At present, the genus is known only from male specimens, but it seems likely that the structure of the lower part of the face is sexually dimorphic, as in Namiocerus .