Greek mythology, Tithonus was a handsome mortal who fell
in love with Eos, the goddess of the dawn. Eos realized
that her beloved Tithonus was destined to age and die.
She begged Zeus to grant her lover immortal life.
Zeus was a jealous god,
prone to acts of deception in order to seduce beautiful
gods and mortals, and he was not pleased with Eos's
infatuation with a rival. In a classic Devil's Bargain,
he granted Eos's wish -- literally. He made Tithonus
immortal, but did not grant him eternal youth.
As Tithonus aged, he
became increasingly debilitated and demented, eventually
driving Eos to distraction with his constant babbling.
In despair, she turned
Tithonus into a grasshopper. In Greek mythology, the
grasshopper is immortal. (In a close cultural parallel,
the Chinese believed that locusts live forever). This
myth also explains why grasshoppers chirp ceaselessly,
like demented old men.
found on web.