The very next time the opportunity offers itself, dust off a little of the mealy powder with a small and very soft brush on to a strip of white paper or a slip of glass, and examine it with a powerful lens or the low power of a compound microscope. What a sight you will then behold! Each little particle of dust is a beautifully formed scale, stamped with a number of minute rounded projections, and often displaying the most gorgeous colours. A great variety of designs and tints are often exhibited by the 'dust' from a single wing. Take, for instance, for your inspection, scales from the wing of one of our commonest insects, the Small Tortoiseshell Butterfly (Plate III), and you will be surprised at the pleasing contrasts. But when your curiosity leads you to deal with others in the same manner, the varied display of forms and colours is simply amazing. [Illustration: FIG. 2.--PORTION OF THE WING OF A BUTTERFLY FROM WHICH SOME OF THE SCALES HAVE BEEN REMOVED.] In order that we may learn still more of the structure of the wings of the _Lepidoptera_, we will examine a portion of one from which some of the scales have been removed, again bringing the lens or the microscope into our service. We now see that the scales are arranged in rows with great regularity on a thin and transparent membrane, which is supported by a system of branching rays. And the membrane itself, in parts which have been laid bare, is marked with regular rows of dots--the points at which the scales were originally attached by means of short hollow rods. The framework that supports the thin membrane we have spoken of as consisting of a system of _rays_, but to these the terms _veins_, _nerves_, _nervures_, or _nervules_ are more commonly applied by various naturalists. We cannot do better, however, than adhere to the name originally used, for the structures in question do not perform the functions of veins, though at first they contain blood, nor are they themselves parts of the nervous systems of the insects to which they belong. The result of our examination of the wings of butterflies and moths has been to justify the application of the term _Lepidoptera_; but we must now study other equally important and interesting features of the structure of these insects. First, let us note the general form of the body. [Illustration: FIG. 3.--BODY OF A BUTTERFLY--UNDER SIDE. 1-7, segments of the abdomen; 8, anal extremity; _a_, antennae; _b_, tarsus; _c_, tibia; _d_, femur; _e_, palpi; _f_, head; _g_, thorax.]