Author: (Snellen, 1903)
Adult: wingspan 22 mm in males; forewing ground colour varying from bright orange-yellow to blackish brown; apical part of forewing reddish, wing scattered with silvery shining and bluish-leaden spots; hindwing bright yellow, apical fifth blackish.
Wingspan females 32-40 mm; forewing ground colour varying from reddish-fuscous to brownish-black, covered with irregular series of round dots. Hindwing bright yellow, apical fifth black.
B. triphaenella male
B. triphaenella var. melanoptera
External characters: 22 mm wingspan. Head and palpi blackish violet; antenna whitish, ringed black, ciliations white. Abdomen blackish violet with light yellow anal tuft. Forewing without costal fold, costa strongly arced at base, concave before middle, slightly curved towards apex, apex broadly rounded; termen outward-oblique beyond apex, inwardly oblique beyond vein M1. Ground colour varying from bright orange-yellow to brown, scattered with whitish-silvery shining dots; a blackish-violet triangular spot on base of wing; some blackish and purple scales on one-sixth of dorsum; a very narrow suffused dark purplish streak along costa, dilated posteriorly, interrupted by silvery shining spots. Apical part of wing reddish-purple, scattered with ochreous-yellow scales and dots and with shining bluish-leaden dots; inner margin diffuse, suffused with blackish-brown, convex; apical area scattered with ochreous-yellow scales and with shining bluish-leaden dots; a yellow suffusion at angle in termen. Cilia brownish-black, mixed with yellow at angle in termen. Hindwing bright yellow, apical fifth blackish; cilia blackish (Diakonoff, 1950a; Yasuda, 1975b).
male genitalia B. triphaenella
Genitalia: Tegumen moderate. Uncus broadly rounded apically, densely bristled; gnathos moderate, with a strong broad point; length of socius less than one-third of that of gnathos. Valva elongate, little dilated and densely bristled distally, obliquely truncate apically; sacculus moderately broad but strong. Transtilla narrow, straight. Aedeagus short, tubular, its orifice with somewhat indented edge. Cornuti absent.
Bathypluta triphaenella female
B. triphaenella var. nox female
External characters: 32-40 mm wingspan. Head bright ochreous mixed with reddish-fuscous, tuft on vertex reddish-fuscous; thorax bright ochreous with reddish-fuscous markings: an anterior and a median transverse band and a median longitudinal streak on mesothorax; metathorax dark brown, a brush of long hairs on each side. Abdomen golden-yellow, posterior half of each tergite dark bronze-brown and all segments with a quadrate bronze-brown lateral patch; anal tuft golden-yellow. Forewing reddish-fuscous, covered with irregular series of round dots, which are more or less completely edged with leaden metallic shining scales; a somewhat darker reddish-ochreous patch of the ground colour at disc beyond middle. Cilia ochreous mixed with fuscous. Hind wing broad, elongate-semiovate, termen only slightly concave, bright yellow, apical fifth black. Cilia black from apex to tornus, whitish-yellow beyond.
female gen. B. triphaenella
Genitalia: 7th sternite not sclerotized, emarginate ventrally. Ostium broad, funnel-shaped. Sterigma very narrow in middle, slightly dilated at the sides, only lamella postvaginalis connected with ventral arms of anterior apophyses. Ductus bursae short; corpus bursae very long; no signum present.
Forewing ground colour varies in both males and females; in dark specimens it is dark brownish-black.
Larvae were collected from August till December.
Adults are day-flying.
Larvae are a minor pest of the tea shrub and the Cinchona tree, feeding on the leaves.