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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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