252 INSECTS 



Hiding places for parasites are also limited and that is 

 a matter of great moment, for some species seem to be 

 dormant or in hiding for very long periods. Alto- 

 gether, it may be said that in all that he does on the 

 farm and in the orchard, the farmer and fruit-grower 

 favors those species that feed upon his cultivated 

 crops, and turns the natural scale against their enemies. 

 That he does not suffer more, is merely an indication 

 that these bird and animal friends that he eliminates, 

 and even the predatory beetles, are not the most im- 

 portant checks of the injurious forms. 



Another way in which man interferes with the 

 orderly course of nature is in the introduction of plants 

 from other countries, well adapted to live in the new 

 locality but unable to resist the insects native to that 

 place, and so giving them an undue advantage. But 

 this is not a circumstance to the mischief done when 

 an adaptable insect is introduced into a new country 

 where it is unknown to the parasites and predatory 

 forms native to that country! The wine-growing dis- 

 tricts of Europe imported from America some of our 

 vigorous American stocks and with them the Phylloxera 

 as well. Now the Phylloxera in its native home is not a 

 serious pest and there was no reason to believe that it 

 would or could ever become such. But the European 

 vines proved absolutely non-resistant and succumbed 

 to injuries where the American vines would have shown 

 no sign. The attempt to control this insect in Europe 

 has cost millions of dollars and it is still an annual 

 charge of many thousands on the various governments 

 and growers. The difference between the American 

 and European stocks is merely a matter of adaptation, 

 our native varieties having become used to the insect 

 when present in normal abundance. There is no specific 

 native enemy to the Phylloxera and conditions in Euro- 



