Legrand explains that on the day he found the bug on the mainland coastline, Jupiter had picked up a scrap piece of parchment to wrap it up. Legrand kept the scrap and used it to sketch the bug for the narrator; in so doing, though, he noticed traces of invisible ink, revealed by the heat of the fire burning on the hearth. The parchment proved to contain a cryptogram, which Legrand deciphered as a set of directions for finding a treasure buried by the infamous pirate Captain Kidd. The final step involved dropping a slug or weight through the left eye of the skull in the tree; their first dig failed because Jupiter mistakenly dropped it through the right eye instead. Legrand muses that the skeletons may be the remains of two members of Kidd's crew, who buried the chest and were then killed to silence them.