ARTHROPOD A 



209 



below ground, or may remain on the leaves of the vine, forming 

 galls and laying eggs which develop parthenogenetically. Mam 

 acres of vineyard have been devastated by this insect. 



In this same suborder arc many curious insects, such as the tree 

 hoppers ( Fig. 207), little animals shaped like a beechnut, doing- 

 no particular harm ; 

 the leaf hoppers, found 

 on grain, grapevines, 

 and roses ; the spittle 

 insect, whose larva? 

 produce the so-called 

 "frog spittle" seen on 

 grass stems during 

 the summer; and the 

 cicadas (Fig. 208), 

 whose music is famil- 

 iar in country places. 

 The sound is produced 

 by the males, which 

 have two large, parch- 

 ment-like sacs at the 

 base of the abdomen, 

 provided with strong 

 muscles, which cause 

 them to vibrate. Our 

 commonest cicada is 

 about five centimeters 

 in length, when the wings are closed, black and green in color, 

 and requires about two years for its complete metamorphosis. 

 The periodical cicada, or seventeen-year cicada, incorrectly called 

 locust, lives only a few weeks as an adult ; it deposits its eggs 

 on trees, and the larva? pass to the ground, where they remain for 

 another seventeen years ; at the end of that time they emerge 

 and become mature. Another species lives only thirteen years 

 underground. 



The third group of Hemiptera has the wings thickened at 

 the base and thin at the tip, and further is provided with a 

 more or less distinct neck. According to their habits they 

 might be classified as aquatic, semiaquatic, and terrestrial. The 



FIG. 209. Belostoma, the giant water bug. natural size. 

 (Drawn from a preserved specimen.) 



