This very interesting species was described and admirably figured by Dr. Boisduval in the French “Annales de la Société Entomologique” (1840); that gentleman considered it to be a Satyride allied to _Satyrus rohria_, _caumas_, etc.,[K] which it somewhat resembles in the form of the wings. In the French “Annales” (for 1851) M. Lefebvre published a note upon the species, in which he criticised Dr. Boisduval’s paper, and stated that the fossil species, instead of being allied to _rohria_, was evidently a _Vanessa_—that the strong, tail-like projection belonged to the front, and not to the hind wings, and represented the angular projection which occurs in all true Vanessidæ, as an example of which he instanced _Vanessa_ (_Junonia_) _Archesia_ of Cramer. This remarkable note was, moreover, accompanied by figures of the species, representing the tail both upon the front and hind wings. In the same volume of the “Annales” Dr. Boisduval gives an excellent answer to M. Lefebvre’s observations, in which he well remarks, “Nous n’avons jamais vu une seule espèce avec les ailes [190] supérieures anguleuses et appendiculées, et les ailes inférieures arrondies comme avec un compas;” and certainly, did such an insect ever exist, its wings would be utterly useless as organs of flight, for they would invariably carry it downwards. In all insects which have small and rounded hind wings, the costa of the front wings always far exceeds the inner margin in length and strength,[L] whereas in M. Lefebvre’s insect the reverse would be the case.