Polyhymno oxystola is a moth of the Gelechiidae family. It was described by Meyrick in 1913. It is found in South Africa (Mpumalanga). The wingspan is 11-12 mm. The forewings are rather dark fuscous, the dorsal area lighter. There is a rather broad shining white median longitudinal streak from the base to near the termen, posteriorly acutely pointed, edged beneath by a streak of dark fuscous suffusion. There is a white line along the costa from near the base to near the middle, then running obliquely into the apex of the median streak. A suffused white streak is found beneath the submedian dark fuscous streak from before the middle of the wing to its extremity, sending a suffused oblique branch to the tornus. There is a silvery-metallic acutely angulated transverse line beyond the apex of