Philampelus helops Walker, 1856, List Specimens lepid. Insects Colln Br. Mus. 8: 180. Type locality: "Port Natal" <<[Malaysia,] Penang [Pinang]>>.
Synonym. Philampelus helops Walker, 1856.
Synonym. Philampelus orientalis R. Felder, 1874.
Wingspan: 104--126mm. An unmistakable grey-green species with a characteristic large oval olive-brown spot at the base of the forewing upperside. Forewing upperside with a large, oval, basal brown patch; discal spot with an additional black spot just anterior to it; apex with a broken black line distally bordering an olive-brown costal patch that ends abruptly at vein M1. Forewing underside similar to Rhagastis velata; postmedian costal spot smaller than in Cechenena helops papuana. Hindwing upperside pale tornal patch larger than in Cechenena helops papuana. Hindwing underside with dots on veins more distal than in Cechenena helops papuana. Labial palp segment 1 with a sharply defined apical cavity. Forewing outer margin very weakly scalloped; apex less acute and produced than in Cechenena helops papuana. Abdominal segments 1 and 2 with a lateral black patch. Underside of abdomen less white than in Cechenena helops papuana.
In the male genitalia, uncus apically flat, truncate, slightly sinuate. Gnathos compressed, outline of ventral surface strongly curved in lateral view. Harpe almost cylindrical, 3-4x as long as medially broad, much longer than in Cechenena helops papuana, apex obtuse, rounded. Aedeagus apical processes much shorter than in Cechenena aegrota, but longer than in Cechenena helops papuana. In the female genitalia, lateral margins of sterigma quite sharply raised. Ostium bursae large, edges weakly raised in a lyre-shape.
China: vi (Guizhou; Hainan)
Larval hostplants. Tetrastigma (Vitaceae).
China: Yunnan (Cangyuan; Gaoligong Shan); Guizhou (Fanjingshan, Tongren County); Hainan (Longhushan, Wenchang City).
Nepal, Bhutan (Irungbam & Irungbam, 2019), northeast India (Arunachal Pradesh), Great Nicobar Island (Singh, Ahmad & Chandra, 2021), Thailand, southwestern China, Vietnam, Malaysia (Peninsular, Sarawak, Sabah), Indonesia (Sumatra, Java, Kalimantan, Sulawesi), the Philippines (Palawan, Balabac).