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Rhombocentra Gen. n.

Type species: semipurpurea Warren.

The single species in this genus was misplaced in Rhomborista Warren (type species devexata Walker, India) but does not accord in morphology with Spaniocentra Prout (see below) or Chloromianta Warren (type species ferruginata Warren, India, Peninsular Malaysia). All have the general features attributed to the Rhomboristiti (Geometrini). The male antennae are bipectinate to three-quarters where the pectinations taper away. Veins Rs and M1 are stalked in the hindwing but M3 and CuAl are not. There are setal patches on the male third sternite. In the male genitalia the uncus and gnathus are strong, the socii moderate to weak; there are no coremata; the valves have strong ornamentation, usually a spine or spines, on the sacculus; the saccus is broad, normal. In the females the ovipositor lobes are of the normal geometrine type, but there is no signum in the bursa.

Rhombocentra is distinguished by a very large brown patch of the Spaniocentra type on the forewing and a distinctive central claw-like harpe on the valve of the male genitalia. There is no pouch between the bases of the valve sacculi (present in Rhomborista and Chloromianta) and the aedeagus lacks the spining and cornuti of Spaniocentra. In the female genitalia the ductus and bursa are narrow, unsclerotised. The lamella antevaginalis has lateral patches of scale bases. In Rhomborista the ductus and basal part of the bursa are strongly sclerotised, the latter fluted, and there is a tongue-like process at the ostium.

Both Rhomborista and Chloromianta have more irregular wing patches, the former with dentate wing margins edged with chain-like markings. Rhomborista has a massive, spatulate process arising from the base of the valve costa as well as a narrow, digitate saccular process. Chloromianta has only a long, slender saccular spine. The Philippines (Luzon) species mianta West has male genitalia as in the type species of Chloromianta and should be placed in that genus, comb. n.

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