INSECTS. 



121 



NOTE. In 1864 chinch-bugs caused a loss in wheat and corn of 

 $100,000,000 ; and in 1850 their ravages in Illinois alone amounted to 

 $4,000,000. 





FIG. 147. Different stages of the chinch-bug, a, egg; b, newly-hatched 

 larva ; c, larva after first moult ; d, larva after second moult ; e, pupa ; 

 /, perfect insect. 



Water-Measure Insects (Hydrometrida). These 

 are narrow, boat-shaped insects, having long legs with 

 which they dart over ponds and 

 streams. The Halobates (Fig. 148) 

 is found on the ocean, hundreds of 

 miles from land, with its eggs. 



Water-Boatman (Notonectida). 

 These aquatic insects dart about 

 upon their backs with great rapidity, 

 using their hind-legs, that are edged 

 with strong cilia, and blade-like, as 

 oars. They fly, swim, and dive with 

 equal ease. The eggs are attached 

 to aquatic plants. 



Harvest- Flies (Cicadida) 

 The seventeen-year Cicada (Fig. 149) 

 is wedge-shaped, with a broad head 



and prominent eyes. The shrill sound is made by a drum- 

 like organ at the base of the abdomen. The eggs, num- 



FIG. 148. Halobates, an 

 insect that goes to sea. 



