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Peratophyga Warren

Type species: aerata Moore = hyalinata Kollar.

Synonym: Euctenostega Prout (type species hypsicyma Prout) syn. n.

This genus brings together a number of different species groups with a variety of structures in the male genitalia. Two features of the forewing indicate it to be a natural grouping: vein M2 has migrated anteriorly to become stalked with M1 at the anterior angle of the cell separate from the radial system; there is a distinctive kidney-shaped fovea, concave dorsad, with transverse carinae, situated immediately dorsad from CuA in the cell (Fig. 1). The fovea is unique within the Ennominae. It is lacking in Euctenostega but has probably been secondarily lost as the only species included shares a number of other features, including distinctive wing pattern, with P. spilodesma Prout.

The species groups have a variety of facies types, but one feature common to most is a pale postmedial band that contains dark spots. These spots indicate the irregularity of the vein spacing on the forewing caused by the anterior migration of M2. Only P. xanthyala and relatives, convergent on Zamarada in facies, lack this band: they are also unique in showing strong sexual dimorphism.

The male antennae are bipectinate in all groups except that including the type species, where they are strongly ciliate. There are no definitive features in the male or female genitalia (though the signum is not circular but bilaterally symmetrical on a linear base) at a generic level but, as with the facies, such features serve to delimit species groups. These are as follows:

The typical group: P. hyalinata (India to China and Japan), P. venetia Swinhoe. The wings are brown or yellowish brown, the bands broad, yellow, fawn, hyaline. The male genitalia have the ventral portion of the valve deep, triangular, the dorsal arm sharply right-angled centrally. The aedeagus vesica has a basal cornutus and, in venetia a distal one that is secondarily scobinate, tending towards the condition in the P. trigonata Walker group. The signum in the bursa has its base set more or less longitudinally: it is transverse in the other groups when present.

The P. trigonata Walker group: trigonata and allies as described below, flavomaculata Swinhoe, bifasciata Warren (Hainan, Burma). Species in this group have the wings almost blackish, traversed by yellow white bands. The aedeagus vesica has a distal cornutus with secondary spining, massive in all except the sister-pair of flavomaculata and bifasciata. This pair has the valve simple, triangular. In the remaining species the valves are bilaterally asymmetric, with complex spining along the costal margin, adpressed in the undescribed Sulawesi species (slides 15626, 15884), but in prominent erect clumps in trigonata and two new Bornean species. These three are characterised by extreme asymmetry of the valve, triangular processes laterally on the tegumen, and the basal part of the bursa longitudinally corrugate and ridged internally with small spines.

The Euctenostega group: P. hypsicyma, P. spilodesma and a new species, P. hypsidesma described below (all Borneo). The wings are reddish pink to grey, banded and irrorated dull yellow. The forewings have irregular bands and a weaker submarginal. In the male genitalia the uncus has lateral setose lobes subbasally. In hypsicyma and hypsidesma the fovea is lacking.

The P. sobrina Prout group: this consists solely of P. sobrina, a large species with bluish grey wings, obscure fasciae and highly modified male genitalia: the arms of the valve and corema are long, narrow: the uncus has socii and a pair of massive ear-like processes arising subbasally from the dorsal surface. The bursa copulatrix lacks a signum.

The P. xanthyala Hampson group: P. xanthyala, P. oblectata Prout (Seram) and an undescribed species from Sulawesi: (slide 6414). The facies is similar to that of Zamarada species, with a green, hyaline basal zone, and there is sexual dimorphism, particularly strong in the more easterly species. The male genitalia have the ventral portion of the valve tapering, incurved, and the dorsal arm is strongly angled, with an additional subbasal dentation.

The genus, though broadly Oriental, has by far its greatest diversity in Borneo.

The larva of the type species was described by Singh (1957) as close in key characters to that of Zamarada, differing in having four pairs of setae on the anal shield instead of five.

In Japan the type species has been recorded by Sato & Nakajima (1975) from Hypericum (Guttiferae). Singh noted the species from an 'unknown creeper'.

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