THE HYDASPIDES were Naiad Nymphs of the River Hydaspes in India. They were nurses of the vegetation god Zagreus, the so-called first Dionysos.
Nonnus, Dionysiaca 22. 390 ff (trans. Rouse) (Greek epic C5th A.D.) :
"And a Naias Nymphe in the river [Hydaspes of India red with the blood of the Indian's slain by Aiakos] unshod, unveiled, peeped out of the stream and cried--‘Kinsman of the Naiades [Aiakos was son of the Naias Aigina]! With the blood of Zeus in your veins! Pity the holy water of the river that fell from Zeus! Indians enough your spear has destroyed. Cease to call for the tears from the tearless Naias Nymphai! A Naias of the water was your own mother; yes, I hear that your Aigina was a River's daughter. Think who brought you forth, and you will no longer defile a River. I will go away to another stream, one without stain., I will go down to the sea, and seaborn Thetis is ready to receive me. Let this river of blood be the care of the Erinyes and Dionysos.’
So spoke the Nymphe, the Naias of the waters, and soaked in blood plunged into the bloodstained water of her father [Hydapses]."
Nonnus, Dionysiaca 23. 270 ff :
"Companies of Hydriades (Water-Nymphs) were driven naked from their homes under the waves [when Dionysos set the streams of Hydaspes aflame], swift-footed, bare, unveiled. One Naias, renouncing her native water now on fire, dived unveiled into the unfamiliar Ganges; another with dry limbs sought a home in noisy Indian Akesines; another Naias Nymphe wandering over the mountains, a maiden unveiled and unshod, was received by Khoaspes near Persia . . .
[Hydaspes cries out to Dionysos:] ‘The Naiades flee from my stream: one dwells in a watery home at my source, one leaves the deep for the thicket, and stays with Hadryades in the woods; another migrates to the Indos, another escapes on dusty feet to hide among the thirsty rocks of Kaukasos, or passing to Khoaspes dwells in strange rivers and in her father's water no longer . . . The stream you have crossed is no stranger to your name for I have washed another Dionysos [i.e. Zagreos] in my bath, with the same name as the younger Bromios, when Kronion entrusted Zagreos to the care of my nursing Nymphai.’"
- Nonnos, Dionysiaca - Greek Epic C5th AD