Natural Order--_Notodontæ_. The larva is naked, has sixteen feet, and is, in different genera, furnished with excrescences, and apparent distortions in various parts of the body. The eighth or last pair of feet, and three last segments of the abdomen, are elevated; when the insect is at rest, the head and first segment are raised in a similar manner. In one genus (containing Camelina) the head and extremity of the abdomen nearly meet over the back, when raised in this singular manner. The posterior feet are frequently useless in walking; in some genera, entirely obsolete. The pupa is smooth, in a cocoon, mostly among dead leaves on the surface of the ground: sometimes it is glutinous, and interspersed with fragments of wood, like the last. I confess I am exceedingly puzzled both with the contents and extent of this order; but this arises from my having seen so few of the species in the larva state. Ptilophora plumigera, figured by Mr. Curtis,[48] I had always considered a Notodonta; but the larva evidently excludes it from the order, and, I should imagine, places it among the Noctuæ; where among them I know not, for I have not the slightest idea of any congeners, either of the larva or imago. The larva from which a collector of Lepidoptera could expect to obtain such an imago would be unicolourous, stouter in the middle, elevated in the penultimate segment, and more attenuated towards the head.[49] Pygæra appears doubtful at first, but when observed quite at rest, and in a perfectly natural position, elevates the head and tail, though in a much less degree than the typical genus. Mr. Curtis's genus Notodonta contains several good species, which may be considered as typing the order, as Ziczac, Tremula, and Dictæoides. The first species, Trepida (the Peridea serrata of Mr. Stephens,) seems more nearly related to Endromis. Both these may, however, probably belong to the order Notodontæ, and be situate near the approach to the central order Phalænæ. Petasia cassinea and Episema cærleocephala appear to be genuine Noctuæ, and very near Chareas graminis, and Rusina ferruginea, as far as my very imperfect knowledge of these four species will allow me to judge. Clostera is another departure from the type; but this may be accounted for, in some degree, by its close proximity to Hepialus, from which genus it borrows its remarkably short antennæ, and other peculiarities. It seems a strange perversion of judgment to place Platypteryx at the end of or among the Geometræ; but Linnæus did so, and that is enough. Hubner, Haworth, and a few others, positively ventured, in this glaring instance, to refer this genus to the Bombyces; but their ideas were thought to be wrong, and their judgment was, _nem. con._ reversed. I have elsewhere expressed a wish that my readers should convince themselves, and the frequent occurrence of the larvæ of Platypteryx and Cerura would afford any naturalist abundant opportunity of ascertaining, that they can be referred to but one