Genus Periacerus Viraktamath & Parvathi

Periacerus Viraktamath and Parvathi 2002: 488 . Type species: Periacerus lalithae Viraktamath, by original designation.

Diagnosis. Ochraceous, pronotum wih dark brown to black band on posterior margin. Crown and face dorsad of ocelli transversely striate. Mesonotum longer than pronotum. Clypoclypellar suture absent. Clypellus in basal 0.66 strongly depressed, lora raised. Forewing with three subapical cells. Male antennae with subapical disc. Male sternite VIII and IX with anterior apodemes well-developed. Metabasitarsomere with three platellae flanked on either side by one seta (Fig. 40G). Male pygofer with basal fracture, without ventral process. Subgenital plates broadest in midlength, well-sclerotized, pigmented, held vertically, with long marginal thin hair-like setae. Style elongate, with well-developed preapical lobe bearing 2–3 prominent long setae, apophysis with thin narrow laminate process laterally near apex. Aedeagus U-shaped, dorsal apodeme well-developed, shaft compressed with subapical gonopore on ventral surface. Ovipositor extending well beyond pygofer. Valvula I broadest at midlength then tapered distally to a pointed apex, dorsal sculpturing strigate, sculptured area occupying 0.66 to 0.75 distal length. Valvula II angularly raised and widened at base frome where the toothed area starts, with basal hyaline area, toothed area occupying 0.5–0.66 distal length, teeth prominent and either close to each other or slightly away from each other.

Remarks. Viraktamath & Parvathi (2002) adequately characterized the genus and commented that this genus is similar to the African genus Pandacerus Webb (1983) as they have very similar female genitalia and differentiated Periacerus based on basally constricted clypellus, longer latero-frontal suture above the antennal pit, distinct basal lobe of subgenital plate, dorsolateral fracture of the male pygofer in addition to closed inner and median subapical cells. From Idioscopus it differs in having sclerotized subgenital plates that are held vertically, lateral laminate process of the style near apex and the aedeagus lacking long processes. Three species are included in the genus from the subcontinent.

Key to species of Periacerus Viraktamath & Parvathi

1. Frontoclypeus with median and lateral dark brown to black stripes (Fig. 41C); male anal collar process with distal rounded lobe crenulate (Fig. 41G) (Sri Lanka)............................................ .. P. lankensis Viraktamath & Parvathi

- Frontoclypeus without such stripes, may be with median brown stripe traversing entire length, and clypellus with dark brown stripe (Figs 39C, 40C); male anal collar process with distal rounded lobe not serrate (India).......................... 2

2. Aedeagal shaft apex hooked, without subapical lateral tooth (Fig. 40K)........................ P. lalithae (Viraktamath)

- Aedeagal shaft apex not hooked, with subapical tooth (Figs 39 IJ).................. P. bidentatus Viraktamath & Parvathi