forms of mouth are but modifications of the same model, adapting it to different functions. The sheath, horny and tubular in the Gnat, soft and muscular in the Fly, is the lower lip; the piercing lancets in the former are the jaws, which are inconspicuous in the latter. The elegant coiled spire of the Butterfly consists of two tubes, which are the lower jaws, greatly lengthened; and the labial palpi, stout and hairy, stand up on each side of them: the other essential parts can be detected only by the skill of the anatomist.

Some of the most interesting of the phenomena which occur in the economy of Insects, are the transformations which they exhibit in their progress of growth; the changes of their form being frequently so great, that it would be impossible, but for the testimony of experience, to avoid the conclusion that the same insect, in infancy, youth, and adult age, belonged to widely distinct and remote orders of existence. We shall enter into some details of this interesting subject in our next chapter.

CHAPTER XVII.

INSECTA (Insects).

Continued.

How delightful is the season, when the Butterflies begin to spangle the fields and woodlands! Welcome visitants they always are, in their airy grace and beauty; not less welcome than the flowers on which they alight, and whose brilliant hues and delicate petals are rivalled by their painted and filmy wings.

"The Butterflies are come !" Yes, it sends a thrill of pleasure through the heart, after the long dreary winter, to see the first Butterfly of the season sailing on its broad sylphic pinions in the warm beams of a calm April morning.

Perhaps it is the pretty little Orange-tip (Mancipium cardamines), that attendant on early spring, coursing along some rural lane; or the Brimstone (Goneptery.c rhamni), hovering over a perfumed cluster of primroses, itself scarcely to be distinguished from one of them. Perhaps it is the Admiral (Vanessa Atalanta), whose fine scarlet bands afford so rich a contrast to its black velvet wings; or the Peacock ( V. Io), with its gorgeous violet eyes; or the Tortoise-shell (V. urtica), clouded with yel

low and orange and black,-busy among the lowly nettles, attentive to the grand occupation that forms "The Whole Duty of Butterflies," the providing for the continuance of the race, by depositing here an egg and there an egg, on the stems or beneath the leaves of those grim and formidable weeds. But even if it is one of much humbler pretensions, the White (Pontia brassica) of our kitchengarden, still it is a Butterfly, and we look upon it with a hearty welcome, forgiving, and for the moment forgetting, all the robbery it committed upon our cabbage before it was born.

And these frail creatures are worthy of our kindly regard, not only for their association (true children of the sun, as they are) with all that is most lovely in scenery, and most delightful in season, but because of their own personal claims to our admiration. If we capture that Red Admiral or Peacock that is so intent upon the nettles, what a glorious creature should we think we had obtained if we had never seen anything like it before! How light and papery, yet how strong and effective, are these broad wings! with what an elegant pencil has this pattern of beautiful colours been traced! But stay! let us look closer at this painting, aiding our sight with a pocketlens. It is a most exquisite mosaic, fashioned out of innumerable coloured pieces, of regular shape and arrangement.

If we look at our fingers' ends with which we have touched, though ever so lightly, these pencilled surfaces, we see that some of the colouring is transferred to them; and if we have pressed the wing, as in seizing it for the purpose of capture, we find that the finger presents the

pattern of the touched part in all its beauty. Now by touching with the charged finger-end a strip of glass, and placing this latter beneath a microscope, we discover an extraordinary specimen of the Divine handiwork. Hundreds of objects are left adhering to the glass plate, which we know not whether to call scales or feathers. They display considerable variety of form, but the most common is oval, or semi-oval, with a little projecting stem or quill at one end. They are thin and flat, transparent and membranous in texture, with several ribs running lengthwise, the points of which project beyond the end of the scale,

These scales, then, produce the beautiful party-coloured patterns of a Butterfly's wing; but of positive colour they possess individually no trace under the microscope, save a dull smoky appearance. It is by the separation and reflection of the prismatic hues that they appear beautiful, but by what law some reflect none but red, some none but yellow, some none but blue rays, we know not.

On examining the wing that has been denuded of its coloured scales, we see a transparent, dry, brittle membrane, pitted with innumerable punctures arranged in lines; these are the depressions in which the stems of the scales were originally planted. They were so ordered that the extremity of one scale reposed on the base of its successor, overlapping and concealing its stem, so that the arrangement resembled that of tiles or slates on a roof. We have said they are innumerable; the expression is not literally exact, but you will think it excusable when you hear that Leeuwenhoek computed the number of scales on a Silkworm Moth (Bombyx mori), to exceed 400,000; and those which bespangle the wings of the

great tropical Moths and Butterflies, some of which expand eight or nine inches, must be vastly more numerous, since the size of the scales does not at all depend on the dimensions of the wing.

The whole Class of Insects is subject to metamorphosis; that is, the same individual animal in the course of its progress from infancy to adult age assumes an appearance and form, with organs both external and internal, different at different stages of its life. In none of the Orders are these transformations more remarkable than in that which we are now considering, the elegant Order LEPIDOPTERA, the Butterflies and Moths.

The parent Butterfly, seeking on restless wing for the plant which shall form a suitable food for her unborn young, at length lays on its leaf an egg, cementing the tiny atom to its surface by a natural glue, which immediately hardens. In a few weeks a minute Caterpillar breaks from the prison, and frequently commences existence by devouring with its powerful jaws the horny eggshell which it has just vacated. But vegetable matter is its proper diet, and, by the providence of its mother, it finds its habitation cast on a plant which is suitable for its nourishment; it is like an ox placed in the midst of an unbounded pasture.

The little worm feeds, and feeds, and feeds, with wonderful voracity: it does nothing else in short, and consequently grows with rapidity. It soon finds its skin too strait for it, for this can stretch only to a certain extent, and has no power of actual growth as ours has, and the horny parts, as the head and feet, cannot even expand, being quite rigid. What must be done? It splits its

L