
This detail is located on the bottom middle section of the illustration of the Sutra on the Descent of Maitreya, between the image of the second assembly and the central treasure pavilion. It represents a story within the sutra in which Maitreya’s mother, Brahmavati, leads 48,000 noble women and court ladies in renunciation.
Two women are depicted in the process of being tonsured by two nuns. One of the women is believed to be Maitreya’s mother, and the other is also likely to be a women of high status, indicated by the fact that there are servants in attendance around the figures.
For more details, go to the Encyclopedia of Buddhist Arts: Caves T-Z, page 1605.