Semnostoma barathrota is a moth of the Gelechiidae family. It was described by Meyrick in 1918. It is found in India (Assam). The wingspan is about 14 mm. The forewings are dark fuscous with a whitish blotch along the basal fourth of the dorsum and a grey-whitish blotch, white on the anterior edge, extending along the posterior half of the dorsum and termen to near the apex, widest above the tornus, where it reaches three-fourths across the wing, including a fine black longitudinal line in the disc in the posterior portion, its posterior end occupied by a blotch of grey suffusion. There is an oblique blue-leaden-metallic line from four-fifths of the costa to just beyond this blotch. The apical area beyond this is brownish, with three whitish costal dots separated by dark fuscous, the last