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Diomea
rotundata Walker
Diomea
rotundata Walker,
[1858] 1857, List
Specimens lepid. Insects Colln Br. Mus., 13: 1110.
Diagnosis.
This and the next two species are very similar, and identification is best
confirmed from the male genitalia. The wings are a steely greyish black, marked
with black, including prominent discal spots and sinuous postmedials consisting
of lunules in the spaces, concave distad, with the acute junctions of the
lunules tipped white (though this is not always evident). There is often a
larger white mark on the forewing costa in this position, and sometimes a slight
one at the hindwing dorsum though never as pronounced as in nigrisuffusa.
There is an irregular black submarginal of variable thickness that, on the
forewing, is expanded into blocks subdorsally and at one third from the costa,
with a smaller block on the costa. In rotundata these
blocks are less prominent, represented by broadening of a more continuous black
band. On the hindwing there is a longitudinal rectangle of rather rufous brown
subtornally. In the male genitalia of rotundata the
saccus is rounded, the valve relatively deep, and its saccular spine is long and
evenly curved. In dialitha Hampson (see below) the tegumen is somewhat more
distinctly shouldered, the saccus is squared, and the saccular spine is much
shorter, apically blunt rather than acute; the dorsal margin of its base extends
almost to the costa, where it forms an irregular angle. The third species is
new, and diagnostic characters of the male genitalia are given in its
description.
Geographical
range. Indian Subregion, Taiwan, Sumatra, Borneo, Philippines, Sumba.
Habitat
preference. Bornean records consist of a female from Kuching and a male
from the vicinity of Pontianak in Kalimantan. Both are lowland localities.
Biology.
Bell (MS) reared the species in India. The shape is typical of fungusfeeding
noctuids. The prolegs of A3 and A4 are lacking, the rest strong but short.
The
whole larva is dirty white with indistinct pink marbling and a pink spot
dorsally at the rear of each segment. The head has glossy tubercles but no
setae; primary setae are present on the body.
The
young, thin larva is transparent, glossy, but has conspicuous black setae on
chalazae. It lies looped in a 'Z' on the lower surface of the bracket fungus
growing on old wood. This lower surface is white, spore-bearing being on long
white filaments or gills. Pupation is on the tree or the fungus in a
tight-fitting, semiovoid cocoon that incorporates chewed rotten wood or fungus.
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