During the early part of last spring I obtained from a small maple tree three cocoons of Anth. polyphemus. In due time two fine females made their appearance, and a few days later, on examining the box again, I found suspended from the lid (wire gauze) a black looking specimen, which at first sight appeared to be a ♂ promethea. On closer inspection, however, I found it to be a beautiful aberration of Anth. polyphemus ♂. As it is the first one I ever found or heard of during nearly twenty years collecting, I send you herewith a meagre description, which may be the means of bringing another specimen like it to the notice of the entomological world.