Adult - Wingspan 24-28 mm. Antenna filiform; scape with black scales basally; flagellum with grey scales and cilia; Labial palp whitish, second and third segments with black rings, one and a half on medial, two on apical, segment. Basal part of proboscis greyish; frons and vertex grey with black scales on top. Thorax grey with four black spots; tegulae grey with a pair of black spots at base. Forewing overlaid with 15 black dots on grey background, and a row of 7 marginal dots. Hindwing orange-yellow, apical patch dark brown, covering 1/7 of hindwing; cilia yellow. Forelegs and midlegs grey with black rings, hindleg orange-yellow with black tarsal rings. Abdomen orange-yellow, tergites with small round dots, sternites 1-6 with pairs of rounded dots on each segment.
Male genitalia - Uncus bifurcate with deep medial incision; anterior part of gnathos long, with more or less equal, strong teeth, posterior part wide, membranous; labis long, thin, hairy. Valva elongate, distally curbed, saccular and apical parts covered densely with strong hairs, costa of valva long; cucullus sclerotized falciform, with apex rounded. Aedeagus gun-shaped carina with strong, tin sclerotized ring, vesica armed with long, pectiniform bundle of long spinules.
Female genitalia - Ovipositor strongly sclerotized, anterior apophyses fused with lamella postvaginalis. Lamella postvaginalis large, sclerotized; scobinated, inflated emergence large, elongated. Antrum with fine sclerotized half-ring, dorsal surface with diffusely dentate zone. Ductus bursae long, tubular, helicoid with several coils. Signum very large, more or less smoothly sclerotized, with crenulated margins, a deep crease horizontally.
Adulte are nocturnal. Larvae making simple silk web and feed on leaves of Ehretia resinosa (Boraginacae) in Taiwan (Wei, et al., 2007). The population in Hawaii also utilizes Cordia subcordata and C. sebestena (Moriuti, 1963; Legrand, 1965; Sattler, 1967) as the hostplant. It is occasionally regarded as pest species in Hawaii. Sattler also noticed the differences in size, wing colouration and female genitalia between populations of different regions, but if these differences reflect genetic differentiation or morphological plasticity due to environmental factors is yet to be investigated in the future.
Psecadia nigroapicella Saalmüller, 1880, Jahresbericht Senckenbergische Naturforschende Gesellschaft 1879/80: 310 (Type locality: Madagascar. Type in SNG)
TAIWAN. Kaohsiung city: 1♂, Takow, Formosa, 21.IV.1905, A. E. Wileman leg. (NHM); 7♂♂8♀♀, National Sun Yat-Sun University, IV.2004. L. C. Shih leg. (NSYSU). Pingtung county: 5♂♂5♀♀, Kenting National Park, Kenting Forest Recreation Area, III.2005. C. H. Wei leg. (NSYSU).
Global distributionOne of the most widely distributed Ethmia species in the world, ranging throughtout Madagascar, Seychelle Islands, India, Myanmar, Kei Island, Samoa, Hawaii, and Taiwan.
Distribution in TaiwanOnly occurring in the coastal forests in Kaohsiung, Pingtung, Green Island (Lu-Tao) and Orchid Island (Lanyu).