Type species: rufescens Butler.
Synonym: Brachybasis Swinhoe (type species rufescens) praeocc.
Brachybasis is a junior homonym of a genus-group name in Neuroptera (Fletcher,
1979). Fletcher considered that rufescens was congeneric with albistellaria
Walker (N. India, Burma), the type species of Paradecetia Swinhoe.
However, a more detailed examination of the morphology of rufescens indicates
that it does merit generic status.
The antennae are narrowly unipectinate, the pectinations broad,
flattened, lamellate as in Paradecetia. In Auzea Walker, the type
genus of the subfamily, they are simply lamellate. The facies of albistellaria
is pale yellow with ochreous yellow fasciae: the hindwing is flushed pinkish
and has an irregular submarginal row of silvery spots. The facies of rufescens
is more similar to that of Decetia species, but with dots on veins
and in the spaces in the hindwing postmedial area, rather than just the former.
In the male genitalia there are extreme differences: the uncus is
broad, sometimes bifid; the capsule is broad, rather than narrow; the saccus is
longer; the valve is divided with an additional, curved, slender process from
the base of the costa.
In the female genitalia of the type species the ductus is short, the
ostium surrounded by a field of setae anteriorly and laterally, and flanked by a
pair of short, curved, tongue-like processes. The signum is heart-shaped. In the
female of the new species the ovipositor lobes are coplanar. The ostium is very
narrow, the ductus long, slender and the bursa ovate with a narrow, transverse,
crescent-like signum. In Paradecetia the signum is more as in Decetia.
The genus has only been found in N. Thailand (specimens of an
undescribed species in Inoue collection), Borneo, Sumatra and New Guinea.
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