This story is actually curiously absent from common literary devices such as metaphors and similes. However, you might like to think about the way that Vera uses onomatopoeia in the second fabrication that she tells at the end of the story to explain Framton Nuttel's swift retirement from the house which the "phantoms" of her uncle and cousins are about to enter:
He was once hunted into a cemetery somewhere on the banks of the Ganges by a pack of pariah dogs, and had to spend the night in a new dug grave with the creatures snarling and grinning and foaming just above him.
The use of the word "snarling" helps to convey the ferocity of the dogs through enacting the sound of their barks. Apart from this, the strength of the story lies in the ironic deception of Framton Nuttel on Vera's part, rather than on extensive use of literary terms.
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