Jātaka No.350 is called Devatāpañha Jātaka (J.iii.152), and the Commentary states that the story will be explained in the Ummagga Jātaka.
The Ummagga Jātaka contains a series of questions asked of King Vedeha by the goddess who lived in his parasol, because she wished to restore Mahosadha to the king's favour. Vedeha inquired of all his wise men, but they could find no answers, and, in the end, he was compelled to send for Mahosadha. The questions, in the nature of riddles, were put to him and he solved them all. vi.370f; the riddles with answers are found in pp.376f.