Cosmopterix ancistraea is a moth in the family Cosmopterigidae. It was described by Meyrick in 1913. It is found in South Africa. The wingspan is about 10 mm. The forewings are bronzy-blackish with a silvery-white subcostal line from the base, not nearly reaching the band, inclined downwards posteriorly. There is a silvery-white median line from the base almost to a projection of the band, as well as a white subdorsal line from one-fourth to the projection of the band. The dorsal edge is white from the base to one-third of the wing and the costal edge is shortly white before the band. There is a rather broad light ochreous-yellowish median band, somewhat narrowed dorsally, the anterior edge marked with two golden-metallic spots, the upper wholly anterior to the lower, followed by a black d