Personification of July. She is wearing a very long tunica dalmatica with wide sleeves over a tunica strictoria with tight, long sleeves.
This is a detail of the late 4th century mosaic of the Months and the Seasons from Carthage Tunisia.
Now in the British Museum https://britishmuseum.org
Garment description:
Fashioning Identity in the Late Roman and Late Antique World: The Case of North Africa (c. AD 200-500)
Amy E. Place, University of Leicester, 2020