Arctornis ferruginicosta sp.
This and the next species are superficially similar in the broad, rusty brown
delineation of the forewing costa on both surfaces that is much more extensive
than in any other species, including corrugata: it also has a grey central
streak. This species has the abdomen entirely white, without a dorsal rusty
brown line. Both species have pale rufous fringes and a black discal dot to the
forewing. The palps and frontal bar are also bright rufous. The legs are not
spotted, though they may be tinged pale rufous in places, such as the
‘elbow’ and tarsi. Both species have a broad uncus, slightly constricted
subapically as in malleuncus. In ferruginicosta this is broad, resembling
the tab on a jigsaw puzzle piece. The valve is elongate-oval, the harpe a bit
longer, slender, slightly sinuous, expanding evenly to an apical club with
increased scobination. The aedeagus has a single process apically rather than
the usual pair.
SARAWAK: Gunung Mulu Nat. Park,
R.G.S. Exped. 1977-8 (J.D. Holloway
et al.) Site 8, February, Camp 1, Mulu, 150m, 385470, mixed dipt.
for., BM lymantriid slide 1592.
Paratypes: 1 as
holotype; 14 general data as holotype but Site 12 (1),
February, FEG 2, Mulu, 200m, 386469, Site 13 (2, slides 1580, 1594), February,
Camp 2, Mulu, 500m, 401464, Site 14 (2, slide 1613), February, Camp 2.5,
Mulu, 1000m, 413461, lower montane forest, Site 20 (5) Mar.-Apr., W. Melinau
Gorge, 150m, 422577, FEG 3, kerangas, and Site 22 (4, slide 1595) April,
W. Melinau Gorge, 150m, 421578, wet kerangas; 1
BRUNEI, 15m, Daerah
Belait, Badas, swamp forest, 26 Feb ‘82 (Lt. Col. M.G. Allen).
Geographical range. Borneo.
Habitat preference. This is a species primarily of lowland forest,
particularly frequent in heath forest, but extends up to the lower montane zone
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