170 THE CANADIAN ENTOMOLOGIST. 



The fact is, that these incursions and ravages of hostile insects repre 

 sent a condition of war. It is only by a quasi-military organization and 

 appropriate weapons suited to the nature of the enemy that they can be 

 conquered. Without recognition of this fact nothing can be done against 

 them, and we must bow our heads and exclaim with the pious' Moham- 

 medan fatalist, " It is the will of God." 



Three subjects yet remain to be considered — the materials to be used, 

 the time of making the attack in force, and the weapons to be employed. 



i. The materials may be either vegetable or mineral, or merely 

 human labor intelligently and persistently applied. The latter is the only 

 effective means of contending against some insects, but in all cases it is a 

 necessary adjunct to the remedies used. These remedies are very 

 numerous, and until a careful investigation is made of the large number 

 already suggested, no proper indications can be given except that those 

 least injurious to man should be preferred, even at greater cost of money 

 and labor ; and that those which kill the insect by contact with its body 

 are likely to prove more effectual than those which destroy by poisoning 

 its food. It may be here observed that the form of apparatus in these two 

 cases must be quite different. In the latter, any contrivance which will 

 sprinkle a fluid or dust a powder on the exposed or upper surface of the 

 leaves will be sufficient ; in the former, in which the poison kills by con- 

 tact with the insect, it must be able to reach the enemy wherever 

 sheltered. 



2. The time of attack must naturally be when the enemy is least 

 able to resist. To quote again from the excellent memoir of Motschulsky, 

 " the most effective and at the same time the easiest mode of opposing 

 the developement of the locusts is the crushing out of the young broods 

 when collected in swarms in the place where they are hatched. Con- 

 sequently the most important thing is to know the nesting place of these 

 destructive pests. In order to discover them and to point out the course 

 to be pursued * * it might be well to send skilful persons * * to 

 make the necessary researches, and these, with the assistance of the local 

 authorities, might seek out the places where the insects abound and 

 establish the necessary regulations for their destruction." (1. c. p. 228.) 

 In the case of the cotton moth it is plain that the attack should be made 

 upon the earliest broods, which are said to appear in the extreme southern 

 part of the country, and from which the migratory swarms which travel 

 northward are supposed to be developed ; also, that the attack must be 

 directed against the caterpillars rather than the perfect insects. 



