The genus _Melitæa_ spreads from the Arctic zone to the tropic of Cancer and some mountain species even farther. Unlike the genus _Argynnis_ in its geographical distribution _Melitæa_ has no Antarctic species. It has its center of abundance in the temperate zone and decreases towards the tropics as well as the arctic zone. According to that peculiarity of the western slope of continents by which the temperate zone is more developed in extent and quality, than in the eastern slopes, the greatest number of species are found in Europe and on our coast. Eastern Asia has very few species, but the genus is better represented on the Atlantic side of this continent, where however, it appears in the aberrant forms of _M. Tharos_, _M. Pyrrha_, etc, whose real nature seems still doubtful and which are at least intermediate between _Argynnis_ and _Melitæa_. The genuine type is very uniform, and therefore the diagnosis of the Californian as well as the European species is enveloped in many difficulties, so that even in regard to many European species known and described for more than a century, the limits of the species are frequently more or less doubtful and nearly every Catalogue gives the series of closely allied species in a different form. California possesses two types wanting to the European Fauna; Europe one type wanting to California. To us the type of _M. Cinxia_ is wanting, to Europe that most characteristic form of _M. Leanira_, which is a very natural transition to the genus _Synchloe_. The other wanting to the old world is that of _M. Pyrrha_, an osculant form peculiar to the new world where it extends nearly as far as the equator. As regards the development of the genus in size and brilliancy of color, the Californians have a decided advantage. The giants of the genus are all Californian and the coloration more bright and more distinct than the somber hues of their less-developed European allies. Like the Argynnides the Melitæae are essentially local. There is no Amphigeic species, and even the Polar species (which in Argynnis are sometimes Amphigeic) are always different in this genus, never occurring both in Europe and America. In the same way the Atlantic and Pacific species seem always to differ.