Achrosis kerangatis sp. n.
11-14mm. This and the next species have the yellow part of the hindwing
much more extensive than in spurca, and the fasciae of the greyer, less
speckled forewings tend to be more complete, though still stronger at the costa.
The principal external difference is in the postmedial mark at the forewing
costa, narrow and at right angles to the costa in kerangatis and broad,
triangular, enclosing an acute angle distad with the costa in calcicola. At
the forewing dorsum the postmedial tends to be more strongly curved in kerangatis.
There are minor but constant differences in the male genitalia. The gnathus
apex is more slender, less truncated apically in kerangatis. The furca
pocket is narrower, uniformly conical in kerangatis, but with a slight
central constriction in calcicola. The valve costa is slightly more
produced from a narrower apex in calcicola. In both species the spines in
the dense patch in the aedeagus vesica are fewer and more robust than in spurca.
Holotype . SARAWAK:
Gunong Mulu Nat. Park, R.G.S. Exped. 1977-8, (J.D. Holloway et al.), BM
1978-206, Site 22, April, W. Melinau Gorge, 150m, 421578, wet kerangas,
BM geometrid slide 10401.
Paratypes: 2 (slide 10389) as
holotype; 1, 3 as holotype but site 20; 5 (slide
12877), 5 BRUNEI: 15m,
Telisai, sandy heath forest with Gymnostoma, various
dates (Lt. Col. M.G. Allen).
Geographical range. Borneo.
Habitat preference. All material is from acid heath forest in the
lowlands, dry kerangas at Telisai in Brunei, and wet kerangas on river terraces
near the Melinau Gorge in Sarawak..
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