THE CICADA'S LAST SONG 249 
blister upon its surface. Upon pressure from ei- 
ther side this blister will be found to " snap," and 
could we but repeat the operation with great ra- 
pidity, a continuous sound would result. The toy 
called the "telegraph ticker" is made on this prin- 
ciple, the blister being made on a strip of steel, 
and the click produced by pressure upon its top, 
the elasticity of the metal bringing it back to its 
original position of rest, and each motion accom- 
panied by a snap as the blister changes sides. In- 
deed, we need look no further than the bottom of 
almost any well-ordered tin pan for a complete 
illustration of this principle. So our cicada is a 
drummer, and his favorite tune is a " roll-call," the 
beats following each other with such rapidity as 
to form a tone. All through the summer we 
hear his strain. Even at this moment, as I write, 
a very long-winded specimen is tuning up in the 
tree just outside my studio window, and I am 
almost moved to give him some good advice. 
Have a care, my noisy minstrel. If it were I 
alone who were within ear-shot of your noise all 
might be well with you, but there are others near 
by to whom your music hath charms. Have a 
care! Only a moment ago I heard an ominous 
hum on my piazza, and upon investigation discov- 
ered a huge sand-hornet prying about the prem- 
ises. He knows what he is looking for, and so 
ought you, if your parents have done their duty 
