Amongst some fertile eggs of butterflies obtained during the past summer of gently pressing the abdomen of ripe females, was one of the above species, the larva of which was carried through four moults up to hibernation. The information gathered is incomplete; but as there is nothing published concerning the preparatory stages of C. Mandan, it seems worth recording, if only to assist others who may be fortunate enought to secure eggs of this rare butterfly. Although widely distribtued over North America, I know of no locality where it is abundant.