The only known mythography attached to Lara is little, late and poetic, coming to us from Ovid's Fasti. She was famous for both beauty and loquacity (a trait her parents attempted to curb). She was incapable of keeping secrets, and so revealed to Jupiter's wife Juno his affair with Juturna (Larunda's fellow nymph, and the wife of Janus). For betraying his trust, Jupiter cut out Lara's tongue and ordered Mercury, the psychopomp, to conduct her to Avernus, the gateway to the Underworld and realm of Pluto. Mercury, however, fell in love with Lara and prepared to force her as she pleaded with a glance, unable to speak. Lara thereby became mother to two children, referred to as the Lares, invisible household gods. However, she had to stay in a hidden cottage in the woods so that Jupiter would not find her.
Ovid mentions the myth of Lara and Mercury in connection with the festival of Feralia on February 21. Lara/Larunda is also sometimes associated with Acca Larentia, whose feast day was the Larentalia on December 23.