38 SOCIAL LIFE IN THE INSECT WORLD 



propagation of the species and the preservation of the 

 individual. The rest of the abdomen presents a spacious 

 cavity, and consists simply of the integuments of the 

 walls, except on the dorsal side, which is lined with 

 a thin muscular layer, and supports a fine digestive 

 canal, almost a thread. This large cavity, equal to 

 nearly half the total volume of the insect, is thus 

 almost absolutely empty. At the back are seen the 

 two motor muscles of the cymbals, two muscular 

 columns arranged like the limbs of a V. To right 

 and left of the point of this V shine the tiny mirrors ; 

 and between the two branches of muscle the empty 

 cavity is prolonged into the depths of the thorax. 



This empty abdomen with its thoracic annex forms 

 an enormous resonator, such as no other performer in 

 our country-side can boast of. If I close with my finger 

 the orifice of the truncated abdomen the sound becomes 

 flatter, in conformity with the laws affecting musical 

 resonators ; if I fit into the aperture of the open body 

 a tube or trumpet of paper the sound grows louder as 

 well as deeper. With a paper cone corresponding to 

 the pitch of the note, with its large end held in the 

 mouth of a test-tube acting as a resonator, we have no 

 longer the cry of the Cigale, but almost the bellowing of a 

 bull. My little children, coming up to me by chance at 

 the moment of this acoustic experiment, fled in terror. 



The grating quality of the sound appears to be due 

 to the little tongues which press on the nervures of the 

 vibrating cymbals ; the cause of its intensity is of course 

 the ample resonator in the abdomen. We must admit 

 that one must truly have a real passion for song before 

 one would empty one's chest and stomach in order to 



