This theater panel depicts two events—both associated with the region around Nysa.
In the center is Kore's return to Nysa. The central figure is Kore (Persephone) standing behind three heads of grain. On her right (our left) is her mother Demeter who has her hand on her shoulder. The male figure on Kore's left may be Hermes.
The other scene, on our right side, focuses on a Nymph, sitting on a bench, nursing the infant Dionysus who is sucking on her breast. There are three soldiers dancing around them—swords and shields are visible. These dancing soldiers are known as Corybants. On the right side of the panel is a reclining river deity, probably Meander, with the river flowing out of a "pot" that is under his left arm.
The description above is an abbreviation of the commentary offered by Egisto Sani on a similar picture on his flickr account. He in turn is dependent upon the original work of Ruth Lindner, "Mythis und Identität."
Lindner, Ruth. Mythos Und Identität: Studien Zur Selbstdarstellung. Stuttgart: Steiner, 1994.