32 



GENERAL ZOOLOGY 



to some creatures which might prey upon it. Observations 

 on the food of birds of the eastern United States seem to 

 dpi show that, so far at least as the birds are con- 

 cerned, these repellent odors are not in all cases 

 entirely effective, since many species of plant- 

 bugs are fed upon quite generally by birds. 



Cicadas. An examination of the large, broad- 

 headed, triangular insects known as harvest- 

 flies, or cicadas, will show that they, too, agree 

 with the foregoing insects in the possession 

 of a sucking-beak. There are several species 

 in the United States, of which the best 

 known is the periodical cicada (Cica'da 

 septen'decim, Fig. 18), usually, but wrong- 

 ly, called the thirteen or seventeen year 

 " locust. 1 ' At the base of the abdomen of 

 the male is a " drum," 

 or sound-producing 

 organ, where a high- 

 pitched note is made 

 by the rapid 



FIG. 18. Periodical Cicada, x 



