No. 4.] THE GYPSY MOTH. 293 



them by burning all near-by vegetation on which they feed. 

 This method is feasible only on waste lands. 



A thorough, scientifically conducted search for and 

 destruction of eggs, supplemented by burhxpping and hand 

 killing, is the only method yet known that can be implicitly 

 relied upon to secure extermination where fire cannot be 

 used. 



Work of this kind is necessarily very expensive and the 

 result is uncertain unless it is followed for several years. 

 Many localities are being cleared in this way each year. 

 This sort of work requires experienced and expert men who 

 are intimately acquainted with the localities in which they 

 work and the distribution and history of the moth therein. 



If all trees and plants in and near each isolated moth 

 colony could be sprayed with an insecticide which would 

 surely and quickly kill all feeding caterpillars without injury 

 to the foliage, it would be the best plan to pursue in the 

 towns least infested. Such an insecticide seems to have 

 been found. If, however, it should fail to be as effectual in 

 the field as is expected, further chemical experiments must 

 be made to find an eftective insecticide. 



The usual plan of fighting noxious insects is to wait until 

 they begin to do visible damage, and then take means to 

 check them. But with extermination as the object it is a 

 grave error to wait until the moths have become apparent 

 anywhere to common observation — until they have begun 

 to do damage, as in the past, and have scattered to a dis- 

 tance from the worst infested spots. They must instead be 

 at once searched for, found and destroyed. Thousands of 

 infested trees have been marked during the past season on 

 each of which only a single caterpillar, pupa, or egg cluster 

 was found. But these single forms of the moth must be 

 found and destroyed if the insect is to be exterminated. 



The statute under which the committee is appointed calls 

 for extermination. The cost of extermination is great. It 

 certainly costs a vast deal more to search for the last egg 

 cluster and the last caterpillar or moth than it would to 

 destroy the majority of them and thus prevent both dissem- 

 ination and damage for the time being. But if larger sums 

 of money than those already appropriated can be secured. 



