INTRODUCTION. 11 



of the grubs, stripped the plants of them much more rapidly than 

 human hands could have done, and were, besides, themselves 

 rendered very fat and fit for the table. But the destruction of 

 vegetation which occasionally results from such causes in this 

 country, is as nothing to that which frequently takes place in 

 warmer climates. No insect is so largely concerned in this as 

 the Locust, of which immense swarms occasionally make their 

 appearance, traversing a great extent of country, and clearing it 

 so completely of its vegetation, as to leave scarcely a trace behind, 

 save the leafless skeletons of the trees and shrubs, whose softer 

 parts they have destroyed. Numerous attempts have been made 

 to keep down the multiplication of these insects by rewards 

 offered for the destruction of their eggs and larvae ; but none of 

 these have been effectual. The sagacious Naturalist, however, 

 who duly considers the relations between different tribes of 

 organised beings, who bears in mind that there is not one species 

 of plant or animal which is not the destined food of another, and 

 who calls to his aid the power which the Creator has given to 

 Man over the animated world not for its destruction, but for its 

 protection and regulation will not have much difficulty in 

 devising a means far better adapted than those just mentioned, 

 for the object in view. He will ascertain what species is most 

 opposed to the one he is desirous of eradicating ; and, by 

 encouraging its multiplication, he will put a far more complete 

 check upon the ravages of his enemy, than by any scheme that 

 may appear more direct in its operation. There is a bird in 

 India, termed the Grakle, which performs the same office in 

 regard to the eggs and larvsB of the Locusts, that the Rook 

 and similar birds fulfil in colder countries. Nevertheless, the 

 inhabitants, being ignorant of the benefits they derive from 

 it. have sometimes sought to exterminate it ; and when they 

 have done this, the same consequences result as when a Rookery 

 has been destroyed in this country ; viz., a great multiplication 

 of the destructive insects formerly kept in check. The following 

 history affords a curious example of this occurrence : 



