INSECT ENEMIES OF WHEAT 177 



regions. From 1889 to 1897 they wrought frightful havoc in 

 Argentina, visiting 347,000,000 acres in the latter year, and 

 destroying 30 per cent of the crops. From 1897 to 1900 the 

 Argentine government spent over $7,000,000 in an attempt to 

 exterminate them. The limit of the invaded region was steadily 

 pushed northward, until in 1901 locusts were entirely absent 

 from the wheat area. They came into Argentina from Bo- 

 livia, the territory of the Chaco, and western Brazil. Bar- 

 celona, Spain, reported a plague of locusts spreading in 1902. In 

 west central Asia, between Askabad and Krasnovodsk, the cereal 

 and cotton crops are commonly devastated by locusts. In 1903, 

 50,000 roubles were set aside to be devoted to the destruction 

 of the insects' eggs in trans-Caspia. It is claimed that sacked 

 flour piled on open railway trucks near Krasnovodsk was de- 

 voured by clouds of rapacious locusts in an incredibly short 

 time. 1 

 In the United States during the early seventies the grass- 



WHEAT PLANT-LOUSE: a, WINGED ADULT; b, FEMALE; c, NYMPH. 



ENLARGED 



hoppers used to invade Kansas "so they would block railroad 

 trains and destroy all vegetation. " In the Red river valley 

 they appeared in great clouds which "cleaned the country 

 quite thoroughly on their flight." 3 These invasions seem to 

 have come mainly from the permanent breeding grounds of the 

 Rocky Mountain locust (Caloptenus spretus Uhler). These 

 grounds were located approximately between the meridians of 

 102 and 112 degrees, and between the 40th and 55th parallels. 



1 Mo. Sum. Commerce and Finance, Feb., 1904, p. 2818. 



2 Industrial Commission, 10:759. 



3 Proc. Tri-State Grain Growers' Ass'n, 1900, p. 184. 



