244 NATURE'S TEACHINGS. 



sufficient number are produced to fill the fissure ; then over all 

 she drags the everted bark. It is easy to perceive where the 

 Cicada has been concealing her brood, by the elevation on the 

 branch. 



"In this manner she deposits about seven hundred eggs, 

 going from branch to branch, her marvellous instinct teaching 

 her to select the most suitable wood for the purpose. The time 

 occupied in constructing each nest was from fifteen to twenty 

 minutes. Her earthly mission finished, she drops, fainting and 

 exhausted, from the branch, and dies. 



" 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 exclu- 

 sively 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 



