Thiotricha tenuis is a moth of the Gelechiidae family. It was described by Walsingham in 1891. It is found on the Seychelles and in South Africa and Gambia. The wingspan is 9-10 mm. The forewings are shining white, with the apex, one costal, and two dorsal oblique streaks, greyish brown. The first dorsal streak commences at one-fourth from the base, is short, stout, outwardly oblique, and reaches to the fold. The second dorsal streak commences about the middle of the dorsal margin, is wide at its base, tapering upwards in a very oblique outward direction, crossing the fold, and attenuated to a slender line in the direction of the apex, before which it meets the scarcely less oblique but much shorter costal streak, which commences at about one-third from the apex. Beyond and near the costal