LITMIR.BIZ

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a small space, the part selected being the eye-like spot at the outer corner of each upper wing. Even to the naked eye this appears as a very splendidly coloured object, yet but little of its exquisite mechanism can be discovered by the unassisted organ. Something more is brought out by a moderately strong lens: we then see the colours disposed in rows, reminding us of the surface of Brussels carpet, or of certain kinds of tapestry work.

      Now let us place the wing on the stage of a good microscope, with the root of the wing pointing towards the light (that is the best position for it); we shall then first perceive that the whole surface is covered, or, so to speak, tiled over with distinct, sharply cut scales, arranged as in fig. 16, Plate II., with the outer or free edges of one row overlapping the roots of the next. These roots being all planted towards the base of the wing, if we place that end next the light (as above directed), the free edges of the scales throw a strong shadow on the next row, which brings out the imbricated effect most strikingly.

      Beginning our observations at the outer edge of the wing, we first notice a delicate fringe of scales or plumes, more elongated and pointed than the surface scales, and of a quiet brown colour. This tint is continued inwards for a short space, gradually lightening, when (as we shift the field of view towards the centre of the wing) the colour of the scales suddenly changes to an intense black; then a little further, and the black ground is all spangled with glittering sapphires, then strewed deep with amethyst round a heap of whitest pearls. Golden topaz—(jewels only will furnish apt terms of comparison for these insect gems)—golden topaz ends the bright many-coloured crescent, and in the centre is enclosed a spot of profoundest black, gradating into a rich unnameable red, whose velvet depth and softness contrast deliciously with the adjacent flashing lustre; then comes another field of velvet black, then more gold, and so on till the gorgeous picture is complete.

      Subject a piece of finest human painting to the scrutiny of a strong magnifying glass, and where is the beauty thereof? Far from being magnified, it will have wholly vanished: its cleverest touches turned to coarse, repulsive daubs and stains.

      Now, bring the microscope's most searching powers to bear upon the painting of an insect's wing, and we find only pictures within pictures as the powers increase; the very pigments used turn out to be jewels, not rough uncut stones, but cut and graven gems, bedded in softest velvet.

      If by gentle rubbing with the finger-tip the scales be removed from both sides of the wing (for each side is scale-covered, though generally with a very different pattern), there remains a transparent membrane like that of a bee's or fly's wing, tight stretched between stiff branching veins, but bearing no vestige of its late gay painting, thus showing that the whole of the colouring resides in the scales, the places occupied by the roots of the latter being marked by rows of dots.

      Hitherto we have been looking at these scales as the component parts of a picture, like the tesseræ of mosaic work; but they are no less interesting as individual objects, when viewed microscopically. To do this, delicately rub off a little of the dust or scales with the finger; then take a slip of glass, and pressing the finger with the adhering dust upon it, the latter will come off and remain on the glass, which is then to be placed under the microscope. These scales may be treated either as opaque or transparent objects, and in both conditions display exceeding beauty, some of these single atoms showing, by aid of the microscope, as much complexity of structure as the whole wing does to the unassisted vision.

      A few of the highly varied forms they present are shown on Plate II. Figs. 23 to 38 are selected from among the commoner forms, as seen by a comparatively low power. The small stalk-like appendage is the part by which the scale is affixed to the wing: it may be called the root. Figs. 17, 18, 19, 20, 21, show some very remarkable forms, which are, so far as has been ascertained, peculiar to butterflies of the male sex, though the use or reason of this masculine badge, only visible to highly magnifying optics, is neither known nor probably to be known at present; but singularly beautiful and curious they are to look at. The little balls at the end of threads are the root portion, and fit into cup-like sockets, placed here and there among the ordinary scales. The surface of these scales is beautifully ribbed and cross-ribbed, and at the upper end is a plume-like tuft of delicate filaments. The curious scale aptly called, from its shape, the Battledore scale, and shown at fig. 22, also belongs to the male of various butterflies, especially those pretty little ones known as the "Blues." Its surface is most curiously ornamented with rows of bead-like prominences.

      Probably one would imagine that in such wee specks as are these scales, one single layer of substance would suffice for their whole thickness (if we can talk of thickness, with objects almost immeasurable in their thinness). But such is not the case, for when scales have been injured by rubbing we now and then find a part with the sculptured surfaces torn off on each side, showing a plain central layer, so that at least three layers—two ornamented and one plain—go to form a filmy body, only a small fraction of the thickness of paper.

      But there are other portions of a butterfly to claim our interest besides its wondrous wings.

      On the creature's head are grouped together some most beautiful and important organs. The most peculiar of these is the long spiral "sucker," which extracts the honied food from the blossoms to which its wings so gracefully waft it. This organ is shown, slightly magnified, at fig. 8, Plate II., and a most delicate piece of animal mechanism it is. Any human workman would, to a certainty, be not only puzzled, but thoroughly beaten, in an attempt to construct a tube little thicker than a horse-hair, yet composed throughout its length of two distinct pieces, capable of being separated at pleasure, and then joined again so as to form an air-tight tube. This redoubtable problem, however, is solved in the construction of this curious little instrument that every butterfly carries.

      The junction of the two grooved surfaces that form the tube is effected by the same contrivance that reunites the web of a feather when it has been pulled apart. We all know how completely it is made whole again, and on examining by what means this result is brought about, we find that it is by the interlacing of a number of small fibres or hairs, just as, on a larger scale, a pair of brushes adhere when pressed face to face; and so in the butterfly's sucker, the two edges that join to form the tube are closely set with minute bristles that, when brought together, interlock so closely as to make an air-tight surface.

      Fig. 9, Plate II., is a transverse section taken near the base of the sucker, the small opening at the top being the food passage, those at the side the air-tubes that supply air for respiration and perhaps assist in suction.

      The tube is probably made with separable parts in order that if its interior should become at any time clogged by grosser particles drawn up with the flower nectar, it may be opened and cleansed by the insect; otherwise, the tube once rendered impassable, the insect would speedily starve, as this narrow channel is the only inlet for the creature's nourishment—its only mouth, in fact, for no butterfly possesses jaws to bite with, or can take any but the liquid food pumped up by suction through this pipe.

      At the end of the proboscis—or, as it is called scientifically, the Haustellum^[3]—there are visible in some butterflies a number of small projections, of the form shown at fig. 10, Plate II., which is a highly magnified figure of the end of the Red Admiral's proboscis. These appendages are generally supposed to be organs of taste, and to aid in the discrimination of food when the pipe is unrolled and thrust down deep into the nectary of a flower.

      The compound eye of a butterfly, wonderful as its structure is, does not greatly differ from that of many other insects, being like them composed of an immense number of little lenses set together to form a hemisphere large in comparison with the insect's head. A portion of one of these eyes forms a pretty and interesting object for the microscope, presenting a honey-comb appearance, the hexagonal lines that mark the division of the lenses being most beautifully geometrical and regular in their arrangement. More than seventeen hundred

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