Yeah, there are two allusions in this poem. The poet makes first allusion to two historical events “Sicilian July,” and “Enta,” a volcanic mountain peak with smoke spewing out. In Sicily, the black snakes are not dangerous but the golden snakes are venomous. Second allusion the poet makes to albatross that ancient mariner shots in “the Rime of the Ancient Mariner.” Initially nobody was in favor to kill the bird, however, later on everybody on the board agreed that it was a right act to do. The mariners later wanted it back because it brought wind with it and steered their ship. Similarly, poet wants snake back as an honored guest to acknowledge poet’s hospitality.