It will be noticed that in the preceding paper on Geometridæ, I have used the Comstockian terms of designating wing-veins. Heretofore these have not been used by any writers on this family of moths; in act, they have been very little used by writers in any family. The reason for this is, not that the system is not a good one, but because it is comparatively new. Most of the older writers have become used to the number system, having employed it in all their previous work, and therefore retain it to preserve uniformity, and perhaps make no effort to familarize themselves with the new dispensation.