Papilio, confirms this idea, by shewing that Cressida is the Heliconian type. We scarcely need remind the student of the natural system that if our theory be correct, this representation, under one form or other, will be found to pervade every group of Lepidoptera. In all such as we have yet investigated, this opinion has been fully verified.

PAPILIO Memnon.

PAPILIO Memnon,

Memnon Butterfly.

Fam. Papilionidæ. Sub-Fam. Papilionæ. Genus Papilio.—Sw.

(Typical form or Sub-genus.)

Sub-Generic Characters.

Specific Character.

Although of sombre colours, this butterfly is imposing in its size, and highly interesting. It is, in fact, that form which is pre-eminently typical of the whole of the Latriellian Papilionidæ. It seems to be common throughout India and particularly so in Java, from whence we possess several specimens. Dr. Horsfield's elaborate work has furnished us with figures of the caterpillar and chrysalis.

In now first defining some of the natural groups of the modern Genus Papilio, it may be as well to state that we give the results of minute analysis, the details of which we hope to lay before the public on a future occasion. In regard to the nomenclature, we have adopted the following principles, suggested to us by a scientific friend of no ordinary authority, as tending to facilitate recollection, without altering well known specific names. Each genus or sub-genus will be named after that species which is its peculiar type; and the new specific name of this species will imply one of its supposed natural analogies. Thus the sub-genus Protesilaus, derives its name from the typical species, while the specific name, now proposed of Leilus, points out the analogy of the group to Urania Fab. The sub-genus we now define, as being in our estimation, pre-eminently typical, retains the name of the genus. It seems also a geographic group, since all the species yet discovered belong to the old world.

CARACOLLA acutissima.
Two-toothed Disk-Snail.

CARACOLLA acutissima,

Two-Toothed Disk Snail.

Class Mollusca. Order Phytophages. Swains.

Generic (?) Character.

Specific Character.

It is seldom we can deliniate more than the covering of testacious animals, particularly where the species are natives of tropical countries. In the present instance we owe this power to the singular fact of this snail having survived a voyage from Jamaica, and peered out upon an English sun. It is now near forty years ago since an intelligent correspondent of our honoured father sent him from Jamaica, a box of land shells: they were carefully packed in moist decayed wood, and enclosed the living animals. The season was summer and the voyage short; the box was immediately opened, and by placing the shells in luke-warm water, the animals of every one slowly emerged from their shells. Of their ultimate fate we know not: but that celebrated artist and entomologist, the late Mr. Lewin, then a guest in the house, executed highly finished drawings upon vellum of each species; and from one of these our present figures are faithfully copied. At the request of our friend Dr. Leach, a copy was also made by some one and transmitted to Baron de Fèrussac, for his great work upon Land shell, where it will be found engraved at pl. 58. fig. 2. M. Guerin has re-copied this latter figure, but as both are inaccurate, without any fault of these gentlemen, (who never saw the original drawing of Lewin) we have now represented it correctly.

PRINIA familiaris
Indian Wren warbler.

PRINIA familiaris,

Indian Wren-warbler.

Family, Sylviadæ. Sub-Family, Sylvianæ. Sw. Genus,