Final answer:
Maenadic rites were biennial events traditionally held in the winter month in Callatis on the Black Sea, possibly coinciding with the time new maidens reached puberty.
Step-by-step explanation:
The student's question pertains to the periodicity and timing of ancient maenadic rites. Traditionally, these rites were biennial, happening once every two years. The Bacchae by Euripides provides evidence that this was already established practice in ancient times. These ceremonies, linked to maenadism—a form of female initiation rites—required this interval possibly to allow new generations of maidens to reach puberty. As for the timing within the year, in Callatis on the Black Sea, the biennial Mysteries were celebrated in the winter month, indicating a specific seasonal context for these rituals.