Hair devoted to Proserpine
Till a lock of hair is devoted to Proserpine, she refuses to release the soul from the dying body. When Dido mounted the funeral pile, she lingered in suffering till Juno sent Iris to cut off a lock of her hair. Thanatos did the same for Alcestis, when she gave her life for her husband. And in all sacrifices a forelock was first cut off from the head of the victim as an offering to the black queen.
Hunc ego Diti acrum jussa fero, teque isto corpore solvo. Sic ait, et dextra crinem secat ... ... atque in ventos vita recessit.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894