The excellent results obtained by a study of both male and female genital organs when determining specimens of this difficult genus in connection nith my paper on the “Lepidoptera of Seton Lake, B. C.” have led me to continue this work with a view to clearing up the numerous synonymical tangles in our Canadian species. The variability within the limits of a single species, the poor condition of much of the type material, and the failure of authors such as Taylor, Pearsall and Swett not only to recognize each other's species, but to realize the wide-spread distributiion of the individual species, hare all contributed to produce a muddle of specific names which has been almost impossible to unravel by a mere study of external characters.