TRIBE BOLETOBIINI
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Diomea rotundata Walker
Diomea rotundata Walker, [1858] 1857, List Specimens lepid. Insects Colln Br. Mus., 13: 1110.


Diomea rotundata


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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