1911 Encyclopædia Britannica/Demetria
DEMETRIA, a Greek festival in honour of Demeter, held at seed-time, and lasting ten days. Nothing is known of it beyond the fact that the men who took part in it lashed one another with whips of bark (μόροττον), while the women made obscene jests. It is even doubtful whether it was a particular festival at all or only another name for the Eleusinia or Thesmophoria. The Dionysia also were called Demetria in honour of Demetrius Poliorcetes, upon whom divine honours were conferred by the Athenians.
Hesychius, s.v. μόροττον; Pollux i. 37; Diod. Sic. v. 4; Plutarch, Demetrius, 12; Daremberg and Saglio, Dictionnaire des antiquités.