Antoninus Liberalis, Metamorphoses 17
When Galateia of Phaistos in Crete became pregnant, Lampros prayed to have a son and said plainly to his wife that she was to expose her child if it was a daughter. When Lampros had gone off to tend his flocks, Galateia gave birth to a daughter. Feeling pity for her babe, she counted on the remoteness of their house and – backed by dreams and seers telling her to bring up the girl as a boy – deceived Lampros by saying she had given birth to a son and brought the child up as a boy, giving it the name Leukippos. As the girl grew up she became unutterably beautiful. Because it was no longer possible to hide this, Galateia, fearing Lampros, fled to the temple of Leto and said many a prayer to her that the child might become a boy instead of a girl. Leto took pity on Galateia because of her unremitting and distressing prayers and changed the sex of the child into a boy’s. In memory of this change the citizens of Phaistos still sacrifice to Leto Phytie (the Grafter) because she had grafted organs on the girl and they give her festival the name of Ekdysia (Stripping) because the girl had stripped off her maidenly peplos. It is now an observance in marriages to lie down beforehand beside the statue of Leukippos
Antoninus Liberalis, Metamorphoses 35
Leto, after giving birth to Apollon and Artemis on the isle of Asteria, went to Lykia, taking her children with her, to the baths of Xanthos. As soon as she arrived in that land, she came first upon the spring of Melite and wanted very much to bathe her children there before going on to Xanthos. But some herdsmen drove her away so that their own cattle could drink at the spring. Leto made off and left Melite. Wolves came out to meet her and, wagging their tails, led the way, guiding her to the River Xanthos. She drank the water and bathed the babes and consecrated the Xanthos to Apollon while the land which had been called Tremilis she renamed Lykia (Wolf Land) from the wolves that had guided her. Then she returned to the spring to inflict a penalty on the herdsmen who had driven her away. They were then still washing their cattle besides the spring. Leto changed them all into frogs whose backs and shoulders she scratched with a rough stone. Throwing them all into the spring she made them live in water. To this day they croak away by rivers and ponds.
Apollodoros, Bibliotheka 1.118-122
When Zeus slew Asklepios with a thunderbolt, Apollon became enraged and in retaliation murdered the Kyklopes, for they designed the thunderbolt for Zeus. Zeus was about to throw Apollon into Tartaros, but at the request of Leto he ordered him instead to be some man’s servant for a year.
Hesiod, Theogony 404
Phoibe came to the desired embrace of Titanic Koios. Through their union she conceived and brought forth dark-gowned Leto, always mild, kind to men and to the deathless gods, mild from the beginning, gentlest in all Olympos. Also she bare Asteria of happy name, whom Perses once led to his great house to be called his dear wife. And she conceived and bare Hekate.
Homeric Hymn 3
As Apollon goes through the house of Zeus, the gods tremble before him, and all spring up from their seats when he draws near and bends his bright bow. But Leto alone stays by the side of Zeus who delights in thunder; and then she unstrings her son’s bow and closes his quiver, and takes these from his strong shoulders and hangs them on a golden peg against a pollar of his father’s house. Then she leads him to a seat and makes him sit: and the Father gives him nectar in a golden cup welcoming his dear son, while other gods cautiously take their own seats again, and queenly Leto rejoices because she bare a mighty son and an archer.
Pausanias, Description of Greece 2.22.1
The temple of Hera Antheia (Flowery) is on the right of the sanctuary of Leto, and before it is a grave of women. They were killed in a battle against the Argives under Perseus, having come from the Aegean Islands to help Dionysos in war.
Pausanias, Description of Greece 2.21.9
At Argos is the sanctuary of Leto; the image is the work of Praxiteles. The statue of the maiden beside the goddess they call Chloris (Pale), saying that she was a daughter of Niobe, and that she was called Meliboia at the first. When the children of Amphion were destroyed by Apollon and Artemis, she alone of her sisters, along with Amyklas escaped; their escape was due to their prayers to Leto. Meliboia was struck so pale by her fright, not only at the time but also for the rest of her life, that even her name was changed Meliboia to Chloris. Now the Argives say that these two built originally the temple to Leto, but I think that none of Niobe’s children survived.
William Smith, Dictionary of Greek and Roman Biography and Mythology
Leto is “the obscure” or “concealed,” not as a physical power, but as a divinity yet quiescent and invisible, from whom is issued the visible divinity with all his splendour and brilliancy. This view is supported by the account of her genealogy given by Hesiod; and her whole legend seems to indicate nothing else but the issuing from darkness to light, and a return from the latter to the former.