During a recent visit to the Marseilles Museum, and while examining the rich collection of fossil insects preserved there, my attention was attracted by two specimens of the remains of a fossil butterfly. Although not very well preserved, nor indeed so perfect as the specimen of a fossil butterfly from the same formation, which was described thirty years ago by Dr. Boisduval, it was evident, at first sight, that the remains in question belonged to a different species, since the lateral moulding of the principal wings was very much inflated.