Laudator Temporis Acti

Vergil, Aeneid 12.845-852 (tr. J.W. Mackail):

Twin monsters there are, called the Awful Ones by name, whom with infernal Megaera the dead of night bore at one single birth, and wreathed them in like serpent coils, and clothed them in windy wings. They appear at Jove's throne and in the courts of the grim king, and quicken the terrors of wretched men whensoever the lord of heaven deals sicknesses and dreadful death, or sends terror of war upon guilty cities.

dicuntur geminae pestes cognomine Dirae,        845
quas et Tartaream Nox intempesta Megaeram
uno eodemque tulit partu, paribusque revinxit
serpentum spiris ventosasque addidit alas.
hae Iovis ad solium saevique in limine regis
apparent acuuntque metum mortalibus aegris,        850
si quando letum horrificum morbosque deum rex
molitur, meritas aut bello territat urbes.

W. Warde Fowler, The Death of Turnus: Observations on the Twelfth Book of the Aeneid (Oxford: B.H. Blackwell, 1919), pp. 149-150:

It is better to leave the Eumenides out of account here. Dirae meant for the Romans, who knew of them probably through Etruscan art and lore, horrible creatures of ill omen: the form in which Virgil here pictures them is strongly Etruscan. Cicero, speaking of the science of augury in Div. xvi.29, says: "Etenim dirae, sicut cetera auspicia, ut omina, ut signa, non causas afferunt cur quid eveniat, sed nuntiant futura, nisi provideris." Virgil uses them here with fine effect to mark the approaching end of Turnus. Jupiter sends an evil spirit¹ to the doomed man, to warn him, to confound him, to paralyze his energies.

¹ There is no need for surprise in the fact that the evil spirit is sent by Jupiter; it was the way in which he secured justice for the world. "The Spirit of the Lord departed from Saul, and an evil spirit from the Lord troubled him" (1 Sam. xvi.14).