Corgatha Walker

Type species: zonalis Walker, Sri Lanka.

Synonyms:

• Ausinza Walker (type species aequa Walker, Borneo = zonalis)
• Aventina Staudinger (type species costimacula Staudinger, Russia (Siberia) = *argillacea *Butler)
• Callipyris Meyrick (type species drosera Meyrick, Australia)
• Celeopsyche Butler (type species nitens Butler, Japan)
• Guriauna Walker (type species semipardata Walker, see below)
• Palura Walker (type species implexata Walker, see below)
• Penisa Warren (type species oblataria Walker, Sri Lanka), syn. n.
• Zitna Walker (type species *albicinctalis *Walker, see below).

This genus includes a large number of relatively delicate species that are associated loosely by the sharing of features of the male abdomen. The generic synonymy above, however, brings together some variety in facies type. The type species of Corgatha is one of a group of species where the wings are a uniform brown to reddish brown, with fine, transverse, straight, pale, postmedial, on the forewing, antemedial fasciae. The forewing costa may also be narrowly pale, and the discal mark may be blackish. The type species of Palura has more irregular, zigzag, blackish fasciae on dark brown, but sometimes with exterior white dots associated with them. The forewing costa can be narrowly paler, entire or broken by the fasciae, or the fasciae can be associated with stronger white marks on the costa. This also occurs in the species around Guriauna where the fasciae are dark against a rufous orange ground, more irregular, with the more distal ones often enveloped within black patches, particularly at the tornus of both fore- and hindwings.

Zitna (with Penisa; see p. 140) identifies a cluster of the smallest species with the most diverse range of facies, from the Corgatha and Palura types to more highly coloured species with costal and distal borders that are darker or, in the case of the type species, white and greenish gold on black. The male genitalia are somewhat different from those of typical Corgatha, so there may be a case for separating Zitna from it; it also appears transitional to even smaller species currently placed in Enispa Walker.

The male abdomen has an angled notch in the anterior margin of the basal sternite, flanked by small, short apodemes. The eighth segment is of the framed corematous type but only weakly developed, including any apodemes, which are often extremely obtuse. The genitalia have the tegumen and vinculum narrow, with the saccus usually acute, though with a rounded apex. The uncus is slender, with its strongest curvature over the basal third and often having much of the rest relatively straight, The valves are distinctive, tongue-like, with a strong spine from the costa arising at about the centre to two-thirds and running parallel to, or curving gently round to meet, the dorsal margin of the cucullus. Opposite the base of this, and occupying a slightly interior position, is a much shorter and broader saccular process, its base usually oblique. In Zitna species this process is predominant, larger, perhaps more basal, and often more robust and curved; the costal process is absent.

Species such as minor Moore and rubecula Warren appear intermediate between Corgatha and Zitna in having facies similarities with some of the latter, but having valve processes that are intermediate, with the costal spine reduced to just an obtuse angle at the centre of the margin.

The female genitalia frequently have the ventral margin of the ostium bilobed or notched, set just anterior to the eighth segment. The eighth segment has short to moderate apodemes. There are usually pouches interior to the apodemes, rounded or obtusely angled, but these are lacking in some species. The ductus bursae is moderate, evenly sclerotised. The corpus bursae has a slight appendix and may be coiled to some extent at its base, just distal to the appendix bursae. 
The genus is diverse in the Old World tropics and humid subtropics, perhaps more so in the Indo-Australian area.

C. nabalua Holloway (1976: 15) was transferred to Condate Walker by Holloway (2005), a genus that he considered to be a member of his Saroba Walker group of genera. This genus-group may also belong to the Aventiinae as discussed on p. 81.

Sugi (1987) stated that the larvae of Japanese Corgatha are lichen-feeders They place fragments of lichen on their bodies, but do not form a complete coating as in Enispa (see p. 141). Robinson et al. (2001) listed old records of oblataria Walker, type species of Penisa (see above and p. 140), with larvae feeding on lichen. Records for green plants, such as for C. implexata Walker below, may be just an indication of the substrate on which lichen-feeding occurred.