“Eublemma” castanea Hampson comb. n.

Acontia brunea Hampson, 1891, Illust. typical Specimens lepid. Heterocera Colln Br. Mus., 8: 12, 74.

Diagnosis

The forewings are narrower than in typical Eublemma and all the wings are a blackish grey. The forewings have fine, zigzag black medial and postmedial fasciae, and the marginal zone is more broadly and diffusely marked with black.

Taxonomic note

Poole (1989) assigned brunea to Metachrostis Hübner. A closely related species, paurograpta Butler, found in Australia, was placed in Metachrostis by Edwards in Nielsen et al. (1996). It has longer, slightly narrower valves with shorter processes in the male genitalia. The type species of Metachrostis (velox Hübner, Europe) and its close relatives have a series of forewing fasciae of a more typical noctuid type, irregular, with the medial running through the reniform and the postmedial with a somewhat quadrate bulge distad from the reniform. Unlike in brunea and paurograpta, the hindwing in typical Metachrostis has similar fasciation over its dorsal part that weakens anteriorly, with a paler wedge running in from the margin to the base in the anal area. The male and female genitalia in Metachrostis are much closer to those of Eublemma in structure than are those of brunea and paurograpta, where the male has a tongue-like saccular process that is more basal than the processes in Metachrostis, and the female has a very elongate corpus bursae. However, there is a coil at its base, and the ductus bursae is sclerotised at each end as in Eublemma. The two species are therefore placed provisionally in “Eublemma”, as they appear unrelated to Metachrostis (but see comments in the generic description).

Geographical range

Indian Subregion, Singapore, Borneo.

Habitat preference

There is an old specimen from Pulo Laut. The three taken in recent surveys were all from the limestone G. Api: from lowland forest at 250m; from montane forest at 900m and 1500m.

Biology

The larva in India was described by Bell (MS). The prolegs of A3 and A4 are absent. The body is spindle-shaped, with supraspiracular, rounded, conical swellings on segments A2-4. There is a tumidity dorsally on A8. The setae at the rear are larger and more prominent than those elsewhere on the body. The head is small, roundish, a pale dull orange with darker dots. The body is a darkish olive-green, with fine, double, dorsal and dorsolateral ill-defined whitish lines and a single, obscure supraspiracular one. There are broader white markings transversely across the posterior margins of A8 and A9, and diagonal marks anteriorly to A7, associated with a rusty suffusion. There are bands associated with the prolegs of A5 and A6, that of A5 extending anteriorly over the supraspiracular swellings to the anterior margin of A3 where it runs over the dorsum and flexes back to form a chevron that encloses a triangle of rusty brown with its base on the front margin of A3. There are similar dorsal chevrons on A1, A2 and A4. The thoracic segments have white dorsal and spiracular lines, the space between them suffused fuscous, and the tumidities of A2-4 have a rusty suffusion away from the white marks.

The larvae sit highly looped amongst the flowers of the host plant, feeding on them. Pupation is in a dense, semi-ovoid white silken cocoon covered completely by yellow and brown withered fragments of the flowers.

The host plant was Terminalia (Combretaceae).

Genitalia: