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Thalassodes Guenée

Type species: pilaria Guenée, Tahiti, and west to Sulawesi.

Numerous Indo-Australian tropical species and a number of African and Malagasy ones have been grouped under Thalassodes, but more than one natural group is involved. A strict definition of Thalassodes is presented here, and new genera established for other groups. Most members of all groups have sea-green wings with paler striae and transverse, usually straight, white fasciae, the postmedial of the hindwing angled. The male antennae are of the typical Hemitheiti type mentioned earlier. No attempt has been made to review African representatives, but available dissections of many of the species indicate that they are unrelated to the three genera recognised here.

True Thalassodes have the hindwing more strongly angled at the centre of the margin and usually have the margins of both wings, or at least the hindwing, edged reddish. This red edging is lacking in some other groups.

The male abdomen presents several diagnostic features: there are setal patches on the third sternite lacking in other groups (correlated with the hind tibial hair pencil noted by Prout (1933, Gross-Schmett. Erde 12: 100)), but the eighth segment is unmodified or only slightly so. In the genitalia there are strong coremata (lacking in other groups). The socii are narrow, rather than broad. The valves usually have sclerotised structures, often spined or scobinate, arising from near the base of the transtilla and sometimes near the base of the sacculus. A definitive feature is an oblique band of sclerotisation across the centre of the valve that usually terminates in a small spur near the ventral margin at two thirds.

In the female genitalia the ductus is broad, the bursa small, not much broader than the ductus, and the ostium is broader than both, rather pocket-like in many cases. There is a bicornute signum.

The larvae of several species or their close relatives are described in the section following. Bigger (1988) provided a general description of grass green larvae with prominent conical horns on the head and a dorsal brownish stripe.

The eggs are elliptical with vertical sides and flat tops. The larvae appear to be moderately polyphagous: the type species has been recorded from the families Anacardiaceae, Barringtoniaceae, Euphorbiaceae, Guttiferae, Leguminosae, Myrtaceae, Rosaceae and Sapindaceae (Robinson, 1975; Bigger, 1988).

The genus is diverse and widely distributed in the Indo-Australian and Pacific tropics. There are seven species in Borneo, and one, T. curiosa Swinhoe, tentatively assigned for the reasons given (see Thalassodes curiosa Swinhoe).

There are often problems with establishing the identity of taxa in this genus and those following. Similarity of facies amongst major groups means that establishing 'marriages' is often difficult. Some taxa are based on female holotypes, some on males. The abdomens of these types, or even the whole specimen, may be lost. Inevitably, therefore, there is an element of guesswork, selection of the path of least resistance or following of precedent in the literature in the text that follows. Identities are established primarily on features of male genitalia. Association of females is often tentative. For this reason, only dissected males are included in type series.

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