Eugoa crassa Walker
crassa Walker, 1862, J. Linn. Soc.
Diagnosis and taxonomic
note. This species is the first of a
sequence of six with rather similar forewing facies consisting of a single
blackish discal dot, just interior to a diffuse but broad and conspicuous
postmedial that is oblique and slightly curved so as to be concave distad. The
male antennae are ciliate to serrate, and bipectinate in the sixth species. The
first three species have the hindwings predominantly pale yellow to brownish
yellow, and the rest have it brown or brown over the distal half. The first
three species have lateral flanges to the saccus in the male genitalia. The
largest of the six are crassa and its sister-species, with the postmedial
much more oblique than in bipuncta Heylaerts. These sister-species are
distinguished in the description of the next species.
Taxonomic note. Unfortunately
the type of crassa, a male, is badly damaged, retaining only one hindwing,
and the abdomen proved to be devoid of genitalia. The original description
suggests the forewing facies is characteristic of this sequence of species, the
fasciae oblique, and the hindwing lacks the grey border of inconspicua Walker
which, with indeclaratana Walker, was placed as a synonym of crassa by
Hampson (1900); both are treated as distinct species below. It is therefore
assumed that crassa is as described above or the next species, and is
more likely to be the more lowland of the two.
Geographical range. Borneo.
Habitat preference. The
species is frequent in various types of lowland forest, including that on
limestone, wet heath forest and alluvial forest.
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