ENVIRONMENT FOR LEPTINOTARSA 91 



they " boarded him in such numbers that the hatches had to 

 be closed. . . . They were abundant everywhere and by the 

 end of the year had overrun the entire northern and eastern 

 part of the United States, excepting Maine." 



Sometimes the masses moved faster, sometimes slower, 

 but always they went forward. Like the Israelites of old, 

 they lived and journeyed and died as they traveled. 



MAP OF THE UNITED STATES AND LOWER CANADA 



This shows the chief trends of migration of Leptinotarsa decemlineata between 

 1859 and 1904. (After W. L. Tower) 



It took sixteen years for them to go from Omaha to Boston. 

 Meanwhile every European nation watched the progress of 

 the army and grew anxious. If beetles could cross the 

 Mississippi River, if they could span Lake Erie and 

 reach Canada, what was to hinder them from taking ship 

 for Europe ? What was to save that side of the ocean 

 from the beetle raids of this side, and what should be done 

 as preparation for the possibility of such an invasion ? 



