Forewing ground color white; costal margin smooth, dark brown; barely falcated at apex; subbasal
fascia gray and weakly marked; antemedial fascia light color and broad; medial fascia dark color and very broad; postmedial fascia dark color, broad and slight excurved in middle; subterminal fascia slender,; cilia medium-long, dark gray.
Scutellum: One pair of apical setae, one pair of equally strongly developed subbasal
8a); cymbium with four strong spines in a subbasal
position and slightly inflected retrolaterally; paracymbium simple, elongate, broadened distally and with a scaped basal lobe (Figs.
Two autapomorphic conditions were found in Benirivulus, which are not present in other congeners: a colour pattern of anal fin, consisting of one or two subbasal
rows of reddish brown close dots, sometimes forming stripes, and a broad dark grey distal zone on the dorsal fin (Fig.
This species closely resembles Stachyotis epichrysa but can be distinguished from the latter in having the forewings with narrower subbasal
, antemedian, and postmedian lines and a dark yellowish brown, semicircular patch along the terminal area; the male genitalia with shorter posterior processes on the uncus and upper apical portion of the valva tapering.
Antenna pale brown; segment I with smoky, subbasal
and subapical rings; base and apical 1/ 4-1/5 of segment II dark brown, except for creamy extreme base and apex; segments III and IV dark brown.
1 times longer than wide; subbasal
cell closed, not reaching the wing margin (Fig.
4 with filiform trichoid sensillae, with about 22 serrulae; serrulae at centre saddle-shaped, broadly rounded at apex, with about 3 or 4 flat, irregular posterior subbasal
denticles and two small anterior sub-basal denticles (Fig.
Vesica: Formed of two sinuously curving straps, apex in form of a single, slender, apically-attenuated spine, dorsal surface of spine with at least weak subbasal
indentation (notch), indentation frequently stronger: secondary gonopore well developed, ovoid, subtended by field of spicules pointing apicad.
Elytra with golden setae, except white setae on 1st interstriae, at submedian region of 2nd interstriae, at base of 5th and 6th interstriae and in horizontal strip on subbasal
region from 5th to 10th interstriae (Fig.
The lateral arm had a small, apically rounded subbasal
knob (Tanaka et al.
2), but it differs in the presence of a fuscous subbasal
line on the forewings (present as fuscous shade in S.