very pectinated antennæ and enormously expansive wings, and we may add nocturnal flight: so that such peculiar characters as the thick full body and prodigiously long antlia of Sphinx, the clavate antennæ, erect wings, and diurnal flight of Papilio, argue a departure from, and not an approach to, the type. By a reference to the Diagrams exhibiting the classes of Insecta, and the sub-classes of Lepidoptera, it will at once be observed, that the central group in each case contains types of the surrounding groups. Now after a central group has thrown off a set of six forms, each representing, in general appearance, some group equally extensive with such central group, the faculty or power of throwing off such forms becomes, in a good degree, extinct, or, at any rate, very much debilitated. This can be no unforeseen, but a perfectly natural, and absolutely necessary consequence; for taking either of the two classes which are at present sought after, Lepidoptera and Coleoptera, we must observe, that did either of them possess as varied forms and characters as are to be found in Neuroptera, the essential and distinguishing character of that class, viz. variety, and the harmonious arrangement of the whole sub-kingdom, would both be entirely lost; and it would remain for human ingenuity to locate either of the classes centrally or externally, as caprice, or the love of differing from others, might dictate. I wish it to be observed, that Neuroptera, in the genera Psyche, Cloëon, Termes, Psocus and Mantispa, does not merely assume the form of the genera, Tinea, Chironomus, Formica, Aphis and Mantis, but actually possesses the characters and appearance of the classes Lepidoptera, Diptera, Hymenoptera, Hemiptera and Orthoptera. The obviously homogeneous character of Lepidoptera and Coleoptera, although, probably, containing in every sub-class more species than the whole of Neuroptera, clearly disproves the existence of variety amongst their contents, equal to that amongst the contents of Neuroptera. Yet the power, although weakened, is by no means extinct; for, amongst the central group, Phalæna, we find the sub-classes, Papilio, Sphinx, Pyralis, Tinea, Noctua and Geometra, most faithfully pourtrayed in Lasiocampa, Ægeria, Cilix, Lithosia, Apatela and Orgyia, and not merely the individual genera which may happen to approach. As far as I can discover, after this second series of types the faculty becomes much weaker, and, after a third, ceases entirely. A decided difference existing between the first and second series of types, must on no account be lost sight of, because it so decidedly proclaims the superiority of the first: in the first instance, the whole character of the central type, Libellula, is completely lost in each of the varying types; whereas, in the second instance, the characters of Phalæna are preserved most decidedly to the remotest ramifications of the class, subject, however, to the variations already pointed out.