Panacra assamensis Walker, 1856, List Specimens lepid. Insects Colln. Br. Mus. 8: 160. Type locality: [Bangladesh,] Silhet [Sylhet].
Synonym. Panacra assamensis Walker, 1856.Synonym. Enpinanga labuana oceanica Rothschild & Jordan, 1916.
Wingspan: 55mm. Strongly sexually dimorphic. In the male, forewing outer margin crenulated posterior to M3 (as in Enpinanga vigens and unlike Enpinanga borneensis). Forewing upperside similar to Enpinanga borneensis but postmedian band dark brown, running from inner edge to Cu2, beyond which it rapidly fades out, and lacking the slightly transparent cream spot on the postmedian line between Cu1 and Cu2. Forewing underside basally mostly red as far distal as the ragged submarginal line. Hindwing upperside similar to Enpinanga borneensis but orange-buff median band clearly visible across entire wing as far as Rs. Upperside of head and thorax with a broad lateral stripe, darker and thus more prominent than in Enpinanga vigens, as dark as in Enpinanga borneensis, but not, or barely extending onto abdomen.
In the female, forewing upperside similar to Enpinanga borneensis but ground colour paler grey and small black circular discal spot conspicuous. Hindwing upperside with outer marginal area darker than rest of the wing, unlike Enpinanga borneensis and Enpinanga vigens, which are much more uniform on the outer margin; inner margin almost uniform, unlike Enpinanga borneensis and Enpinanga vigens.
In the male genitalia, uncus slightly longer than gnathos. Valve with a few stridulatory scales. Harpe a slender, acute, curved process (similar to Enpinanga vigens). Aedeagus apical process short, parallel-sided, rounded apically, denticulate; twice as long as wide (similar to Enpinanga borneensis).
China: 13.v (Guangdong); 24.vi (Guangdong); 10.viii (Hong Kong); 8.ix (Hong Kong).
Larval hostplants. In Hong Kong on Tetracera sarmentosa (WangDa Cheng, pers. comm. 2020).
China: Yunnan (Yiwu; Lijiang); Guangdong (Guangzhou); Hong Kong; Hainan.
Sri Lanka, Nepal, Bhutan, northeastern India (Subhasish Arandhara, 2016), Bangladesh, Andaman and Nicobar Islands, Thailand, southern China and northern Vietnam.