In some instances, these tribes or sub-kingdoms seem pointed out by nature's self in so decided a manner, that the lisping infant will at once recognise them. Where this is the case, what can definition avail? Let us refer to birds as one of these clearly marked divisions. I single it out as better understood than either of the others. Let us ask, To what does all the arrangement tend which has here been so lavishly bestowed? To utter confusion, volume after volume, essay after essay, open their yawning leaves, and repeat, again and again, one and all, utter hopeless, unintelligible confusion. But if, neglecting the high authorities on the subject _in toto_, we condescend to consult nature, we shall soon perceive that birds readily range themselves in seven good and clearly defined groups; one of which is preeminently distinguished from the rest, and yet partakes in some one or other of its component genera of the characters of all the other groups; such a sub-class must, therefore, be central; and, by a little care in availing himself of the most obvious approaches, the naturalist will find every other sub-class, and order, and genus, beautifully filling up their appropriate situations, without causing any of those distortions which so disfigure every existing arrangement of this interesting tribe. Syrrhaptes, Serpentarius, and all those hitherto parodoxical creatures which seem to have frightened our ornithologists out of their wits, are now not only admissible, but absolutely necessary to connect tribes which no one had previously supposed in the least degree related;--but I will not here forestall, as an attempt to point out the numerous and unlooked-for relations existing among the genera of birds, which the present plan has served to develop, forms the subject of a separate essay, already in a state of forwardness; and the more immediate object of my present inquiry, although a tenant of the air, is not to be sought for among its feathered tribes. I will, therefore, leave these for the present, fully intending that the ornithologist as well as the entomologist shall have an opportunity of examining whether my theory has truth and reason to support it, or whether he must condemn it as an _ignis fatuus_ of the brain.