when I show you separately the substances you now see in combination. In this specimen you see the Schorl is a distinct crystal with six sides, dispersed through the Granite-base. This, therefore, would sometimes be called Porphyritic Granite-in Cornwall it is called Moor-stone. Here is one (Fig. 5), of a still finer grain than the former, in which the Felspar greatly predominates and decides the colour. You can here scarcely distinguish the parts-as far as I can perceive, it contains only white Quartz and Red Felspar. Thus you will find the colour and composition of Granite infinitely various -but the texture is still the same-an appearance of several substances crystalized together, in forms irregular and indistinct. Many other minerals, such as Garnets, &c. are occasionally found imbedded in the Granite, but seldom in such quantity as to influence its general appearance.

MATILDA. I think I have now an idea of Granite, but I could not so readily distinguish its component parts -I should like to see them separately.

MRS. L.-This you shall do-but we cannot to-day prolong our conversation. There is a remarkable variety of Granite composed of Felspar and Quartz only, and so disposed as to have the appearance of written characters-whence it is called Graphic Granite. The probable origin of Granite we must speak of in a future conversation. Its uses you need not to be told. It is one of the most durable of natural productions, and on that account the fittest for building; but its extreme hardness is an objection in the working of it. Many parts of London are paved with Granite. In Dublin, there are some fine buildings constructed of it, of a beautiful kind found in the vicinity of the city. "In Wales, there is very little Granite-in the north of Scotland it is abundant-in England it occurs in Cornwall, Devon, Westmoreland, and Cumberland; and in small quantities in the Malvern Hills of Worcestershire, and Charnwood Forest in Leicestershire."

SERIES OF FAMILIAR CONVERSATIONS ON THE ANIMAL KINGDOM.

CONVERSATION V.

CLASS ARTICULATA-SUB-CLASS INSECTS.
Insects in their Larva State.

PAPA. I am under a promise, I think, of giving you some account of insects and of the changes they undergo; and if you are disposed for it, we will devote this evening to the subject.

ANNA. Thank you, Papa: I have been much wishing for it.

PAPA. I believe I told you that all insects pass through four states: do you remember what they are? ANNA. Yes, Papa; the egg, the caterpillar, the chrysalis, and the perfect insect.

PAPA. Or, to speak scientifically, the egg, the larva, the pupa, and the imago. I am not fond of the pedantry of using scientific words, when those in common use would answer the purpose as well; but as we have no terms in our language that apply to the different states of all insects, it is more convenient, when we speak of them generally, to employ those which have been invented for the purpose.

ANNA. I suppose then caterpillars, maggots, and grubs, are all called larvæ.

PAPA.-Yes; the term larva is applied indifferently to all insects in their second, and pupa, in their third state the words caterpillar, maggot, grub, &c., and chrysalis, nymph, semi-nymph, and cased nymph, definitely pointing out the particular sort of larva or pupa meant; just as in Botany, you know, the common term pericarp applies to all seed vessels, while the several kinds are designated by the names capsule, silicle, legume, berry, &c. Here is a cabbage caterpillar,

which will afford us an excellent specimen of insects in their second, or larva state.

ANNA.-What does the word larva mean, papa?

PAPA.-It is a Latin word, signifying a mask. It was adopted by Linnæus, because the insect, such as it afterwards appears, lies as it were masked, or concealed, under this external form.

ANNA. Do you mean to say, papa, that a butterfly lies concealed in this caterpillar?

PAPA.-Yes, my dear. It has been satisfactorily proved by Swammerdam and other naturalists, that the butterfly, with its organs indeed in an almost fluid state, but still perfect in all its parts, lies incased within the larva. Of this fact you might convince yourself by boiling a full-grown caterpillar for a few minutes, or by laying it for a few days in vinegar or spirits of wine, for the purpose of giving consistency to its parts: a very rough dissection would then enable you to discover the future butterfly. Its wings you would find rolled up into a sort of cord, and lodged between the first and second segment of the body; the antennæ and trunk coiled up in front of the head; and the legs, however different in form, actually sheathed in the present legs. of the insect. But let us examine this caterpillar. You observe that the covering of the body is divided into a certain number of rings, which may be considered the skeleton of the animal, for it has no internal skeleton you know. These rings are united by bands of muscles; two lying on the upper, and two on the under side; by means of which it is enabled to bend its body in any direction, as you may perceive it is capable of doing. I believe I have already told you that insects are much more organized than any of the zoophytes: they have all not only muscles but nerves, which, instead of lying in the back, as they do in larger animals, are disposed in the under part of the body, that they may be secure from injury.

ANNA. And they have a heart and veins too, have

they not, papa? Some lines I learnt the other day seem to imply that they have. PAPA.-Repeat them, will you?

ANNA.

"In thousand species of the insect kind
Lost to the naked eye, so wond'rous small

Were millions joined, one grain of sand would cover all;
Yet each within its little bulk contains

A heart that drives the torrent through the veins;
Muscles to move the limbs aright; a brain;
And nerves disposed for pleasure or for pain;
Eyes to distinguish; sense whereby to know
What's good or bad, is, or is not its foe."

PAPA. All that is said of such very minute objects of microscopic curiosity must rest on supposition alone, for they are by far too small to allow the possibility of any observations on their construction; but with respect to those insects which are sufficiently large to be examined anatomically, I believe it is now fully ascertained that they have neither veins nor heart, and consequently no "torrent" passing through them. Instead of such a complicated apparatus, which their minute structures and short-lived existence do not seem to require, fluids pervade every part of the body without circulation; while air is admitted into it through apertures or air vessels placed along each side. These Spiracles, as they are called, were formerly mistaken for blood-vessels.

ANNA.-Insects then do not breathe as we do.

PAPA.-No-they breathe through their sides. If we had a microscope here we would examine this caterpillar's mouth. Would you believe it, it has jaws and teeth too, and even lips. The mouth does not open horizontally, as ours do, but perpendicularly, or from side to side.

ANNA. I have often watched them eating: they are not long in making a large hole in a leaf.

PAPA. The quantity larvæ eat is astonishing. I believe a cabbage caterpillar like this will consume

more than twice its own weight in twenty-four hours; and the maggots of many flesh-flies will, in a night and day, devour so much as to increase their weight two hundred fold. Indeed the sole object of the larva seems to be the satisfying of its insatiable hunger; and its intestines are almost all stomach, for digesting the masses of food which it consumes. As they eat a great deal, they generally grow very fast, so that a frequent change of skin is necessary to them; for their skin does not, like that of other animals, extend with their growth. I believe all larvæ moult seven, and some even ten times an operation which is attended with considerable difficulty and even pain to the insect; for it loses not only the skin of the body, but even the skull or horny covering of the head, with the jaws and teeth.

ANNA. I should think they cannot eat quite so fast just then.

PAPA.-No, poor things! their new jaws and teeth are too soft to do much execution at first; they soon harden however, and enable them to eat faster than

ever.

ANNA. Have all larvæ jaws and teeth?

PAPA.-Not all the instrument for receiving food depends on the aliment they are destined to feed on: those which live on solid substances have jaws and teeth; but those whose food is liquid, are provided with a tube through which to suck it in.

ANNA. Here are some spots on the Caterpillar's head, I suppose they are its eyes.

PAPA. It is not known exactly what they are, but it is not probable they are eyes; for insects in the larva state do not appear to have the sense of sight, nor indeed any sense but that of touch. You observe that this Caterpillar has six legs.

ANNA. Has it not more than six, papa?

PAPA.-No, my dear: these are the legs which are placed in three pairs near the head; the other little processes which some Caterpillars have, and which you take