ANIMAL BIOLOGY 





After the last molt the animal is complete, and changes 

 no more in size for the rest of its life. There has been an 

 attempt among writers to restrict the term 

 grasshopper to the long-winged, slender 

 species, and to call the shorter winged, 

 stouter species locusts according to old 

 English usage. 



Economic Importance of Grasshoppers. 

 Great injury is often done to vegetation by 

 grasshoppers ; however, the millions of tiny 

 but ravenous eaters hatched in early spring 

 are usually soon thinned out by the birds. The migra- 

 tory locusts constitute a plague when they appear, and 



FIG. 116. 

 COCKROACH. 



FIG. 117. PRAYING MANTIS, or devil's 

 horse. 



FIG. 118. CRICKET. 



they have done so since ancient times. The Rocky Moun- 

 tain locusts flying eastward have darkened the sky, and 

 where they settled to the earth 

 ate almost every green thing. 

 In 1874-5 they produced almost 

 a famine in Kansas, Nebraska, FlG - "9- -MOLE CRICKET. 

 and other Western states. The young hatched away 

 from the mountains were not healthy, 

 and died prematurely, and their devas- 

 tations came to an end. Of course the 

 migrations may occur again. Packard 



calculates that the farmers of the 

 FIG. 120. FRONT \ir t i , e 



LEG OF MOLE West lost $2OO,ooo,ooo because of grass- 



CRICKKT. x 3 . hopper ravages in 1874-5. 



