volumes which he contributed to the 'Species Général des Lepidoptères,' I cannot recall a single instance in which he has suffered structural characters to override superficial; and yet each genus and family is prefaced by a careful statement of structural points which may readily, nay, is almost certain to be mistaken for a diagnosis, until one tries to work with it. For example, in characterizing his Geometrid family Acidalidæ, he correctly states "indépendante bien marquée aux quatre ailes; costale des inférieures isolée de la sous-costale ou simplement rapprochée," of which the equivalent in my terminology would be "vein 5 well-developed, 8 in the hind wings not connected with cell or near base only," which are really essential characters of his genus Acidalia and its allies, and no exceptions are mentioned. Moreover, if the characters given for the Acidalidæ and the Larentidæ, for instance, are compared throughout, it will be seen that there is no absolute distinction between them except in the latter of these two characters, the corresponding point for the Larentidæ being "costale des secondes ailes presque toujours bifide," that is, "8 in the hind wings anastomosing with cell to beyond middle." Now if we proceed to examine the genera attributed to the Acidalidæ, we find the first, Synegia, really has 5 in the hind wings obsolete, and should therefore be placed (not only correctly, but on Guenée's own definition) in his family Boarmidæ; the second, Drapetodes, is not a Geometer at all, but belongs to the Drepanidæ, having 5 approximated to 4 in both wings; the fifth, Pomasia, and the seventh to tenth, Cambogia, Asthena, Eupisteria, Venusia, all have 8 in the hind wings anastomosing strongly with the cell, and belong in truth to the Larentidæ. The family definition has in fact been disregarded altogether. On the other hand, the characters given for the Apamidæ and Hadenidæ, for instance, have little reference to structure, and are practically identical; hence it is not surprising that species rightly referable to the same genus are placed by Guenée, some in one and some in the other of these two families, which are separated from one another by four other considerable families of Noctuæ. Now these are not isolated instances, but fairly typical examples of the whole work; and yet this classification, having been adopted by both Doubleday and Stainton, has held the field in Britain for forty years, and has become so
