Fighting Pests with Insect Alii 



constantly made thai unwittingly new and 

 ious enemies to agriculture may be introduced. 

 The unfortunate introduction of the English 



sparrow into this country is mentioned, and 

 the equally unfortunate introduction of tin- 

 East Indian mongoose into the West Indies as 

 well. The fear is expressed that the beneficial 

 parasitic insects, after they have destroyed the 

 injurious insects, will either themselves attack 

 valuable crops or do something else of an equally 

 harmful nature. But there is no reason for such 

 alarm. The English sparrow feeds on all sorts 

 of things, and the East Indian mongoose, while 

 it was introduced into Jamaica to kill snakes, 

 was found, too late, to be also a very general 

 feeder. As a matter of fact, after the snakes 

 were destroyed, and even before, it attacked 

 young pigs, kids, lambs, calves, puppies, and 

 kittens, and also destroyed bananas, pine- 

 apples, corn, sweet potatoes, cocoanuts, peas, 

 sugar corn, meat, and salt provisions and fish. 

 But with the parasitic and predatory insects 

 the food habits are definite and fixed. They 

 can live on nothing but their natural \^"^\. 

 and in its absence they die. The .Australian 

 ladybird originally imported, for example, will 

 feed upon nothing but scale insects of a j 'ar- 

 ticular genus, and, as a matter of fact, as soon 

 as the fluted scales became scarce the California 

 officials had the greatest difficulty in keeping 

 the little beetles alive, and were actually 

 obliged to cultivate for food the very u 

 137 



