Didigua Walker

Type species: purpureoscripta Walker, Borneo.

Synonyms: Bessara Walker (type species uadratipennis Walker, Borneo) syn. n.; Lasionotella Warren (type species exesa Warren, Borneo), syn. n. Though Bessara has page priority, Didigua has had more recent usage and is therefore treated as senior synonym here.

The species in Didigua are generally duller than in Calymera and Xenochroa, grey, fawn and brown, occasionally tinged green, red or violet. The forewing fasciae are more irregular, usually transverse, and the discal mark is generally more conspicuous. The male hind-legs lack the typical careine modification.

The genus is defined by a number of unique features of the male genitalia that are also shared by Lasionotella. Lasionotella may represent a monophyletic group as defined below, but it is likely that this would render the rest of Didigua paraphyletic. Species attributable to Lasionotella (e.g. by Kobes (1997)) are listed from D. effusa Swinhoe to D. padanga Swinhoe, and may also include D. viridifusa Kobes. Non-Bornean taxa referable to the Lasionotella group of Didigua include the Himalayan species D. viridipicta Hampson and D. immemor Warren comb. rev.

The male abdomen offers no diagnostic features. In the genitalia, the uncus is flexed anteriorly (backwards when viewed from ventrally), sinuous, apically slender and acute but often distinctly broadened basal to this, and then more ‘shouldered’ onto the tegumen (e.g. Fig 344). The tegumen is also shouldered, the shoulders with narrow bands of thickening. The sides of the tegumen are elongate, straight, parallel, with distinct clusters of long setae on large bases. The valves are elongate, rather strap-like, with long setae on similar large bases on the sacculus. The costal process of the valves is overlapped by a basally directed lobe as in Diehlea. The aedeagus vesica varies from ovate, with one or a few robust cornuti, to elongate, with diverticula terminating in clusters of smaller spines.

The female has a pyriform bursa with a slender, often elongate neck set on a short ductus. The neck often has a zone of sclerotisation, sometimes extensive. The signum is occasionally tee-like, more often irregular, even flanged.

Lasionotella falls within this general definition but has more secondary sexual features such as hair tufts on the male hindwing and a variety of coremata in the abdomen. The aedeagus vesica is always of the elongate type. In the female, the bursa always has the neck and basal half of the bursa sclerotised, slightly fluted. The distal part is finely scobinate and contains the signum.

The genus is restricted to the Oriental tropics, with most of its diversity in Sundaland, though perhaps seven species occur in Sulawesi. The species are found more predominantly in lowland habitats than those of Calymera and Xenochroa (Table 3), and have a particularly high incidence of occurrence in forest types on acid soils: heath, swamp and coastal forests. They also show a high level of persistence in secondary and plantation forests (Chey, 1994).

No host plant records have been located.