Since writing my paper (Can. Ent., 263, ante) I have been able to examine a specimen of the Asiatic A. selene. The moth differs from luna, chiefly in the pointed apices of fore wings, the outer margin sweeping inwardly in an even curve. I cannot consider this character of generic value, since precisely the same separates the South American Eacles magnifica from our E. imperialis. In the same species of certain Papilionides, a similar variation has been noted. The exterior bands appear faintly also in certain examples of luna, while the whiter colour is shown by the variety Rossi. Whether this tendency to white is reversionary in its nature, may be questioned. The tails are more developed in the Asiatic species, but (without denuding) I cannot find any neurational differences. I conclude, then, that Leach's term Actias is also applicable to A. luna. On the other hand, the European isabellœ seems to admit of a distinct genus.