“The male, who is always trilling his refrain, goes on, indifferent, or unconscious, that the task of his faithful spouse is finished, singing even, until his time comes--then he too drops beside her. Thus the songs one by one cease,--not only the Cicada’s, but all the forest choir, and give place to blasts that sigh in mournful music through the leafless trees.” The Sirex and several of the larger Ichneumon-flies are often found dead in like manner, and I have no doubt from the same cause. An elaborate description of the beautiful double saws of the Cicada is given by Mr. Westwood in the work already quoted, together with illustrations. THE RIBBON SAW, CORDON OR BAND SAW. Perhaps some of my readers may be acquainted with a saw which has of late years come into extensive use--namely, the Ribbon Saw, Cordon Saw, or Band Saw. This is an endless steel band toothed on one edge, and passing over two wheels. It has the advantage of being of almost any breadth, some being several inches wide, while others are mere narrow ribbons, barely the sixth of an inch wide. The fretwork of pianos and other articles of furniture is cut almost exclusively by the Cordon Saw. A thick piece of wood is cut of the requisite shape, and the upper and under surfaces planed quite true to each other. The pattern is traced on the upper surface, and a very narrow Cordon Saw is then applied to it, cutting completely through the thick block, and adapting itself to all the intricacies of the pattern. The block is then cut into thin slices, so that a number of pieces of fretwork can be made with comparative ease. To those who have been accustomed to cutting fretwork with the slow hand-saw, the Cordon Saw is simply fascinating, the slender steel ribbon cutting through the wood with wonderful rapidity and very little sound. * * * * * BEAUTIFUL as this invention is, it was long ago anticipated in Nature; and the Cordon Saws, which we shall now see, are armed with teeth many more in number, and far more complicated in detail, than those of any saw made by the hand of man. I allude to the Tooth-ribbon possessed by many of our common molluscs, such as the Limpet, the Whelk, the Periwinkle, the Slug, &c. The last mentioned of these creatures possesses a natural Cordon Saw with nearly twenty-seven thousand teeth, and scarcely a tooth that is not elaborately cut into secondary teeth. [Illustration: PORTION OF TOOTH-RIBBON OF WHELK (HIGHLY MAGNIFIED).] [Illustration: RIBBON OR CORDON SAW.] As all these creatures have their teeth differently formed and set, according to the species, it will be impossible to describe them separately. I will therefore restrict myself to the Tooth-ribbon of the common Whelk, a specimen of which is now before me. When viewed through the microscope, it is found to consist of a flat membranous ribbon, on which are set three rows of teeth, those of the outer row being hooked, and those of the inner one plain.