Minerva visiting Envy in order to punish Aglauros. Etching by J.W. Baur, 16--.

Ovid, Metamorphoses, II.752-786. Envy is shown on the left living in a cave on a mountainside with snakes. Minerva, wearing armour, stands outside, propping the door open with a long sword, in order to command Envy to harm Aglauros, who had disobeyed one of Minerva's instructions. 'When the feared war goddess came there, she stood outside the cave, since she had no right to enter the place, and struck the doors with the butt of her spear. With the blow they flew open. Envy could be seen, eating vipers’ meat that fed her venom, and at the sight the goddess averted her eyes. But the other got up slowly from the ground, leaving the half-eaten snake flesh, and came forward with sluggish steps. When she saw the goddess dressed in her armour and her beauty, she moaned and frowned as she sighed. Pallor spreads over her face, and all her body shrivels. Her sight is skewed, her teeth are livid with decay, her breast is green with bile, and her tongue is suffused with venom. She only smiles at the sight of suffering. She never sleeps, excited by watchful cares. She finds men’s successes disagreeable, and pines away at the sight. She gnaws and being gnawed is also her own punishment. Though she hated her so, nevertheless Tritonia spoke briefly to her. "Poison one of Cecrops’s daughters with your venom. That is the task. Aglauros is the one." Without more words she fled and with a thrust of her spear sprang from the earth.' (Ovid, loc. cit., translated by Anthony S. Kline)