“What we have just stated, applies equally to the correlation of species with each other. If we take, for example, the genus _Satyrus_ of Latreille, we perceive that it is composed of an infinite number of secondary groups, scarcely any of which are proper to one country. Thus, in Europe, we have the division to which _Galatea_ belongs, extending along the basin of the Mediterranean, even into Persia; that of _Hermione_, which takes the same direction, and continues to Cachmere; that of _Norna_, proper to the polar regions of the two continents; that of _Nigres_, which inhabits mountainous countries, and is found only at the Cape and at Chili; finally, that of the _Satyres_, properly so called, which are connected with the species of New Holland, some of them with those of Chili, of North America, and Siberia. America and the East Indies, likewise, present groups which in general appearance differ widely from our European species; while there are others which resemble several at the same time. A collection of the _Satyres_ of one country would, therefore, form a sufficiently natural series; but it would appear most irregular when the species of several countries were brought together. “Our method is partly founded on the caterpillar, and partly on the perfect insect. We attach the greatest importance to the caterpillar state, and the characters which it furnishes have often more value in our estimation, than those afforded by the butterfly; but generally these characters confirm each other, in other words, two caterpillars presenting the same characters produce flies which likewise partake of the same generic characters. It will no doubt be objected to us, that it is illogical to deduce characters except from the animals we are attempting to classify. We reply, that by following any other plan we must despair of attaining to a natural method. Besides, it is not necessary to be acquainted with the caterpillars of every species; it is sufficient to study a caterpillar and chrysalis of _Vanessa_ or _Pieris_ to have an exact idea of those of the two genera. Even though it should be very difficult to verify the characters taken from the larva, this is no reason why we should abstain from employing them. It is not merely from the fruit that botanists obtain their characters, but likewise from the flower, and even from the first developement of the vegetable embryo. The flower is to the plant what the caterpillar is to the lepidopteron, and the different modes of metamorphosis have as much value as those of inflorescence.