Miscellaneous Genera VI
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Rhesala Walker

Type species: imparata Walker, Sri Lanka.

Synonyms:
Hingula Moore (type species albolunata Moore, India); Magulaba Walker (type species moestalis Walker, Sierra Leone); Rimulia Saalmüller (type species malgassica Heyden, Madagascar, = moestalis).

The genus consists of small, dark, dark brown species that are distinguished externally by white marks centrally on the forewings that arise to a mark shaped like and ‘X’ or an inverted ‘V’ between the reniform and orbicular. There may be a smaller mark basal to the orbicular and also one associated with the discal spot on the hindwing. The strongest fasciation on all wings is the darker brown postmedial that, on the forewing, flexes round the reniform, and in some species is broadened at the costa. The male antennae are ciliate. The labial palps are typically catocaline.

The male abdomen has the eighth segment of the framed corematous type, but the sternite may be strongly modified in some species (e.g. Fig. 903). The genitalia have the tegumen very much longer than the vinculum. The shape of the uncus is highly variable, from broad and short through elongate, narrow, to crested with hairs and peaked, sometimes with lateral processes. The tegumen is much longer than the vinculum. The valves are simple, elongate and ovate, with the basal saccular portion semi-detached and terminating in a slight distally directed spur on the ventral margin. There may be small coremata associated with this basal structure of the valve. The aedeagus vesica is broad, often with lobes or diverticula, and usually with some scobination.

The female genitalia have the ostium bursae between the seventh and eighth segments. Posterior and adjacent to the eighth segment on the intersegmental membrane is a distinctive zone of dense spining. The ductus is usually unsclerotised, narrow. The corpus bursae is ovate to pyriform and usually contains much coarse spining though may be sclerotised over the basal part (
imparata). The biology of the type species is described below. All host records are from the Leguminosae, the exception being one from Mangifera (Anacardiaceae) (Robinson et al., 2001).

The genus is found throughout the Old World tropics to as far east as New Caledonia and Fiji (Holloway, 1979). R. moestalis Walker is widespread in Africa and the Indian Subregion, and extends to Peninsular Malaysia and Singapore, where it and the type species can seriously defoliate rain trees (Samanea saman) grown for shade and decorative purposes in urban situations. The male genitalia of moestalis are characterised by asymmetry: the species may prove to occur in Borneo, and it is small like R. nigricans Snellen.

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