Matsyapurana 113.15

113.15

pītaśca dakṣiṇenāsau tena vaiśyatvamiṣyeta
bhṛṅgipattrīnabhaś caiva paścimena samanvitaḥ
tenāsya śūdratā siddhā meror nāmārthakarmataḥ //

On its southern quadrant, there is yellow colour, on account of which it is said to have the properties of the Vaiśya caste. On its western quadrant, there is the colour of the wing of a black bee, owing to which it is said to possess the properties of Śûdras.—15.