But there can be little doubt that those arrangements are the most accurate and philosophical which are founded on characters derived from all the different states in which these insects exist. This conviction seems now to be generally entertained, and most writers of very recent date have seen the propriety of acting upon it. In the works of Curtis, Stephens, Horsfield, &c. it has been adhered to to a greater or less extent, and in a general work on Lepidoptera lately published by Dr. Boisduval of Paris, nearly equal importance is assigned to the peculiarities of the caterpillar, chrysalis, and butterfly. As this method presents some new features, and is the last that has been laid before the public, we shall give an account of it along with the accompanying remarks in the authors own words:--“It is not till after a most attentive study of the butterflies of Europe in their different states, and after having collected a certain number of materials on the metamorphoses of exotic species, that we have attempted to group the lepidoptera in a manner different from that hitherto followed, not neglecting, at the same time, the study of those authors who have occupied themselves with this order, that we might be enabled to combine the results of their labours with our own. We do not flatter ourselves, however, that the combinations which we have made are altogether free from blame, any more than those of our predecessors. When occupied with the productions of a single country, the classification is much more easy; the greater number of species associate pretty well with each other, and, if we except a few of the most anomalous, a series is obtained free from much irregularity. In this way, the European species form a pretty homogeneous assemblage, and the same thing holds with regard to those of South America, New Holland, or any other country taken by itself; but when we attempt to classify those of the whole globe, we frequently meet with intermediate genera which interrupt this harmony. If we even take a somewhat numerous genus belonging at the same time to several different countries, we find species which form a passage to other races proper to each of these countries. For example, the genus _Pieris_ of Latreille offers species in America (genus _Leptalis_) which bear a perfect resemblance to the _Heliconii_ in their colour, the length of their bodies, and narrowness of the wings. Others of the same country (genus _Euterpe_) insensibly unite with that division of American _Papiliones_ which is of a black colour with red spots; those of Europe, on the contrary, present certain relations to _Parnassius_, _Pieris Cratægi_ appearing to form the passage to _P. Mnemosyne_, while those of India gradually approach _Colias_ through _P. Judith_ and _P. Panda_, and to _Danais_ with green spots through _P. Valeria_. All other genera of some extent, and distributed over several countries, are in the same condition.