In "The feather pillow" by Horacio Quiroga when the parasites don't have a human to feed on they usually are small, they are parasites of feathered creatures. This parasite, in particular, has been feeding on Alicia's blood, that is why it became so monstrous. We learn about this in the last parragraph of the story.
<span>D. They are written in the format of a business letter.</span>
