CONCLUDING REMARKS. 103 



The experiment of introducing the sparrows had heen 

 tried in New York City, Boston, and elsewhere, with 

 marked success. The ugly caterpillars had fast disap- 

 peared before the inveterate and persistent assaults of 

 those courageous creatures. Nor is this success difficult 

 of explanation. The sparrows were in a strange country, 

 and almost entirely ignorant of its living flora, if we 

 except a few plant-species that are common to Europe 

 and America. In municipal limits this diversity in 

 plant-life is very conspicuous. With insect-life it is 

 otherwise. Almost every tree has its particular occu- 

 pants. While some afford nourishment to but a single 

 species, others yield ample food for a dozen or more. 

 The Phalcenidce, to which our numerous species of span- 

 worms belong, are indiscriminate feeders. Hence, their 

 presence in unlimited numbers wherever trees flaunt 

 their foliage. Those who have studied this peculiar 

 group of insects in their larval stages, know the perfect 

 facility with which they can be identified. In general 

 structure, the closest resemblance obtains between spe- 

 cies, however remote the quarter of the globe in which 

 they have been studied. It is evident from the above 

 remarks that England can form no exception to the rule. 



From these data, we reason that the sparrows were 

 more or less familiar with this portion of our insect- 

 fauna, and consequently manifested no fear of evil con- 

 sequences resulting from the appropriation of such diet. 

 Hence their attacks upon the canker-worm. These 

 assaults would be the more vigorous in situations where 

 there was a dearth of more desirable food. Thrown 

 upon their own resources, nothing edible would be likely 

 to escape their rapacity. 



Immense hosts of insects were formerly destroyed by 



