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Hydrillodes hemusalis Walker
     Bocana hemusalis Walker, [1859] 1858, List Specimens lepid. Insects Colln Br. Mus., 16: 117.

Pseudaglossa buruensis Holland, 1900, Novit. zool. 7: 574, syn. n.


Hydrillodes hemusalis

Hydrillodes hemusalis
Figure 173
Figure 192

See the previous species.

Taxonomic note. The male genitalia of hemusalis vary slightly in the structure of the valve processes through the range of the species. A revised synonymy of hemusalis with illustration of type material was presented by Owada (1992) on the basis of wing pattern. However, his concept of hemusalis was not accurate as it proves on dissection of the holotype (in OUMNH) to be conspecific with buruensis Holland, and the other taxa that he included as synonyms (nilgirialis Hampson, subbasalis Moore and latifascialis Walker) form a separate group, as discussed next.

Hydrillodes nilgirialis (India) is a species distinct from hemusalis as indicated earlier by Poole (1989) who placed hemusalis and latifascialis as synonyms of lentalis but retained subbasalis as distinct. The male of nilgirialis has a distinctive triangular fringe of hair-scales on the underside of the forewing costa centrally; the third segment of the labial palps is slightly downturned, bulbous with dense scaling, brown outside, straw-coloured inside, but with a small brush of paddle shaped, straw-coloured scales dorsally near its base. In subbasalis (Andamans, Peninsular Malaysia), smaller, with a paler medial band on the forewing, there is a similar patch of scales under the forewing but very much smaller, rectangular, with shorter scales that are a paler straw colour. The male labial palps are smaller, the third segment similar to that of nilgirialis but more blackish and with a horn-like process dorsally near its base. The male genitalia of the species also differ. Those of nilgirialis (slide 19747, Sikkim) have a strong, sinuous interior ridge to the valve costa, and its ventral margin is strongly convex distally, with a hook-like process at its extremity, whereas those of subbasalis (slide 19748) have the valve costa less modified, and the ventral margin is more sinuous distally, the hook at its extremity being smaller and closer to the apical angle of the costal part. The aedeagus and vesica ornamentation are similar in the two, but, whereas subbasalis has two small cornuti at the base of the vesica, nilgirialis has one larger, more distal spine and a similar spine at the aedeagus apex. Only females of latifascialis (Sulawesi) have been seen, but they match those of subbasalis in facies except the pale medial band of the forewing is broader. In all three species the sterigma in the female genitalia is similar, the ostium having two shallow quadrate lobes ventrally and two blunt, divergent spines dorsally. All three taxa are best treated as good species for the time being until males of latifascialis from Sulawesi can be identified reliably. The complex belongs to the first group of species discussed under the generic account. No Bornean specimen examined appears to belong to the latifascialis / subbasalis group.

Geographical range. Borneo, Peninsular Malaysia, Philippines, Sulawesi, Buru, Ambon.

Habitat preference. The type material of hemusalis was taken in Sarawak by A.R. Wallace, probably in the lowlands. A further female was recorded from the lower slopes (below 1300m) of G. Mulu by Hose. Only old material of males has been located, from Bidi in the lowlands of Sarawak, and G. Marapok without altitude data. Two females have been taken from secondary and coastal forest near Seria in Brunei. This appears therefore to be a species of disturbed lowland forest.

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