View Image Gallery of Tribe Hypochrosini

Achrosis Guenée Gen. rev.

Type species: pyrrhularia Guenée.

Synonyms: Pagrasa Walker (type species instabilata Walker = pyrrhularia); Sabaria Walker (type species contractaria Walker = rondelaria Fabricius (India)) syn. n.; Isnisca Walker (type species cyclogonata Walker = rondelaria Fabricius) syn. n.; Osicerda Walker (type species alienata Walker) syn. n.; Zomia Moore (type species incitata Walker) syn. n.

The generic names above are brought into synonymy with Achrosis as they share one or more of several features rather atypical of most Hypochrosini: rather elongate forewings with a centrally angled margin (all); weakening of forewing fasciae except at the costa where they are strongly marked; on the hindwing, fasciae are more or less restricted to the tornal zone and the wing in the majority of taxa is broadly yellow or orange anteriorly; the forewing postmedial is irregularly sinuous and often more or less parallel to the wing margin.

There are no definitive features in the male genitalia, though most taxa have the furca symmetric. The aedeagus vesica is frequently scobinate (e.g. typical Achrosis and Zomia) or with localised fields of cornuti (the spurca Swinhoe group) and there are a number of other features that can be used to define subgroups within the genus. There is also considerable variation in the female genitalia.

Achrosis pyrrhularia stands rather on its own in the genus with its pinkish facies, as do the small, variegated brown species in the fulvifusa Warren group. In the latter the genitalia are relatively large with characteristically narrowed valve apices and a slender furca, and the female bursa has a distal disc-like signum and general scobination over the basal half. The Sabaria group is represented in Borneo by alienata Walker, sharing with rondelaria Fabricius apically spinose, rather club-like, symmetric furca arms.

A conical basal pocket to the furca is shared by members of the spurca Swinhoe group, semifulva Pagenstecher and its allies and the lithosiaria Walker complex, all of which have the furca arms small or absent. A. multidentata Warren stands alone in having an asymmetric furca and two groups of stout cornuti in the aedeagus vesica.

In the Zomia group the furca is absent but there are prominent tufts of long setae arising from the sacculus on each side of the furcal pocket. The female bursa is distinguished by two longitudinal bands of scobination, and the lamella vaginalis is strongly sclerotised and somewhat crinkled. The viridapex Holloway pair, with a slight asymmetric furca, may also be related.

Most or all of these groups do not show close affinity with typical Achrosis or typical Sabaria, though most have been placed in the latter in recent treatments (e.g. Holloway, 1976). The alternative to uniting them all in Achrosis on the basis of the characters listed earlier is to erect at least three new genera.

Another reason for keeping the assemblage in one genus for the time being is that members of three groups, A. rondelaria Fabricius comb. n. (unpublished IIE records), a member of the Zomia group (see below) and A. intexta Swinhoe comb. n. (Bell, MS; an Indian member of the fulvifusa Warren group), have been reared from Ixora (Rubiaceae).

<<Back >>Forward <<Return to Contents page

Copyright © Southdene Sdn. Bhd. All rights reserved.