Went to Cambridge and Boston to-day. Dr. Harris says that my great moth is the Attacus luna; may be regarded as one of several emperor moths. They are rarely seen, being very liable to be snapped up by birds. Once, as he was crossing the College Yard, he saw the wings of one coming down, which reached the ground just at his feet. What a tragedy! The wings came down as the only evidence that such a creature had soared,—wings large and splendid, which were designed to bear a precious burthen through the upper air. So most poems, even epics, are like the wings come down to earth, while the poet whose adventurous flight they evidence has been snapped up [by] the ravenous vultures of this world.