ENVIRONMENT FOR LEPTINOTARSA 93 



numbers to be moved onward or to be blown forward as 

 accident might dictate. 



Still they were neither eating nor traveling all the time. 

 Dr. Tower says that most beetles spend from three to five 

 months a year underground in a state of torpor, taking no 

 part in life's activities. But when spring comes and the 

 days are warm, then new life drives them aboveground 

 again. They now creep and fly about and fall to eating 

 spring leaves that are beginning to grow. It is at this time 

 that the farmer is in despair. He cries, "The bugs are upon 

 us!" He arms himself to defeat them. He picks them from 

 the vines by the peckful and the bushel. He puts Paris 

 green on the vines to kill the marauders. He digs long 

 trenches across their pathway, waits until hundreds of thou- 

 sands of them have fallen into these trenches, pours kero- 

 sene oil in after them, touches a match to it, and in a flash of 

 light the beetles have been conquered. No beetle can survive 

 an environment of Paris green or of fire. Man must therefore 

 meet him with these weapons if he wishes to save his crops. 



Now compare the snails of Hawaii with the potato bugs of 

 America, and keep in sight the following facts : 



1. On Oahu, an island forty-six miles long and twenty- 

 five miles wide, there are between two and three hundred 

 species of one great family of snails. In North America, in 

 all the area of the Northern states and of Canada, there is 

 but one species of potato bug. 



2. On Oahu each species of snail must have its own kind 

 of food, else it will die. In America potato bugs live on 

 fifteen or twenty different kinds of plants. 



3. Hawaiian snails move by creeping, and they do this 

 slowly. American potato bugs not only creep but also walk 

 and fly and are blown forward by the wind. 



