96 Life and Immortality. 
so long famous. In the male of the Seventeen-year Cicada 
the musical instrument consists of two stretched membranes, 
one on each side of the body, which are plainly to be seen 
immediately behind the wings. These membranes are 
gathered into numerous fine plaits, and are played upon by 
muscles or cords fastened to their under surfaces. When 
these muscles contract and relax, which they do with great 
rapidity, the drum-heads, which the membranes resemble, 
are alternately tightened and loosened, the effect of this 
alternate tension and relaxation being the production of a 
rattling sound very much like that caused by a succession 
of quick pressures upon a slightly complex and elastic piece 
of tin-plate. Certain cavities within the body of the insect, 
which may be seen on raising two large valves beneath the 
abdomen, and which are separated from each other by thin 
transparent partitions of the brilliancy of mica or highly 
polished glass, tend to increase the intensity of the sound. 
In the winged state Cicada septendecim, as the subject of 
our sketch was named by the immortal Linnzeus, is of a black 
color, with transparent wings and wing-covers, the thick 
anterior edge and veins of which being orange-red. Near 
the tips of the latter there is a dusky zig-zag line which 
resembles in shape the letter W. The eyes, when living, are 
also red, while the legs are a dull orange, which color is 
conspicuous along the edges of the rings of the body. The 
wings expand from two and a half to three and a quarter 
inches. 
About the middle of June the perfect insects make their 
appearance, and as they generally come in large numbers 
they do a great deal of damage. In some localities they 
congregate to such an extent upon the trees as to bend and 
even to break down the limbs by their weight. The din of 
their discordant drums resounds in the woods and orchards 
from morning to evening. As their life is of rather short 
duration, not lasting for a longer period than a month, they 
soon begin to pair, and it is not long afterwards that the 
