Complex sentence: The two older sisters try to stop the Tsar from becoming interested in visiting the island; in retaliation the bumble-bee Gvidon stings each of them in the brow.
Split into simpler sentences: The two older sisters are concerned that the Tsar will become interested in visiting the island, and they try to dissuade him. In retaliation the bumble-bee Gvidon stings each of them in the brow.