19, 20mm, 21mm. The species has facies similar to that of medialis but is a more greenish brown and generally paler. The postmedial is more gently sinuous, less zigzag at the dorsum, and there is no dark medial fascia or orbicular stigma. The hindwing fasciae continue further towards the costa from the dorsum but diverge somewhat more. The male genitalia have the valve more tongue-like, with the costa more or less straight, and the ventral margin curving up to a rounded apex from a vestigial process at the end of the sacculus at three-quarters. The aedeagus vesica is smaller than in medialis but with similar fine scobination. The female genitalia are described in the generic account.
Holotype. BRUNEI: 300m, Ulu Temburong, rainforest, 10.2.80 (Lt. Col. M.G. Allen), BM noctuid slide 19495.
Paratypes: 1 NORD BORNEO: Mont Kina Balu, 5-8.1903 (John Waterstradt); 1 (slide 19855) Poeh Mts, SARAWAK, 3500' [18]92 (A. Everett).
Taxonomic note. Two further species in this group are curated under Lithilaria Rosenstock in BMNH over the Hampson manuscript name ‘plumosa’. This refers to a male from Mindoro in the Philippines with strongly bipectinate antennae. There is a series from Sumatra that Swinhoe (1906, Ann. Mag. nat. Hist. (7), 17: 551) considered to include the female of invenusta but is unrelated to the holotype of invenusta (= undulata).
Geographical range. Borneo.
Habitat preference. The species, like medialis, occurs in both lowland and montane forest.
21mm. The species has facies similar to that of medialis but is a more greenish brown and generally paler. The postmedial is more gently sinuous, less zigzag at the dorsum, and there is no dark medial fascia or orbicular stigma. The hindwing fasciae continue further towards the costa from the dorsum but diverge somewhat more. The male genitalia have the valve more tongue-like, with the costa more or less straight, and the ventral margin curving up to a rounded apex from a vestigial process at the end of the sacculus at three-quarters. The aedeagus vesica is smaller than in medialis but with similar fine scobination. The female genitalia are described in the generic account.