194 BOARD OF AGRICULTURE. [Jan., 



man and the domestic animals, and are carriers of disease. 

 We consider them beneficial when they feed vipon noxious 

 insects and plants ; when they pollinate our cultivated plants ; 

 and when they furnish products that we can use for food, for 

 clothing, and in the arts. Undoubtedly the greatest benefit 

 which mankind derives from the insects as a class comes 

 through the role which they perform in carrying pollen from 

 one plant to another while gathering nectar from the flowers. 

 We fail to appreciate the importance of this fact. If it applied 

 only to the little wild blossoms of the field and meadow it 

 would have no special interest to the farmer. It would make 

 little difference to him whether these plants continued to 

 exist or not — except so far as he may be led to enjoy them 

 for nature's sake — they hold no important place in the 

 economy of his agricultural operations. But when we con- 

 sider that the vast fruit interests of this country and of the 

 world depend upon small insects to pollinate the flowers of 

 trees and plants, this group of animals assumes a position of 

 tremendous importance to agriculture. 



Furthermore, many of our vegetables, especially those 

 consisting of the seed pods or fruits of plants, like cucum- 

 bers, squashes, etc., are pollinated almost wholly by insects. 



Let us review, briefly, some of the great discoveries which 

 have made clear the relation that insects bear to agriculture. 



In the year 1787 Sprengel decided that the nectar in 

 flowers was secreted for the sake of insects. Two years later 

 further study led him to conclude that certain species of plants 

 are unable to exist without insects to fertilize them. Spren- 

 gel's work seems to have passed unnoticed for nearly fifty 

 years, when Darwin, recognizing the truth of it, began his 

 long series of investigations which have so completely revo- 

 lutionized our ideas of plant pollination and shown the mutual 

 adaptations that exist between the organs of plants and in- 

 sects, and enabled him to formulate the law that '" nature 

 abhors perpetual self-fertilization." Darwin published a list 

 of plants which are sterile with their own pollen, but it does 

 not include any of our fruits.* 



It was not until 1894, twelve years after Darwin's death, 

 that the United States Department of Agriculture gave to 

 the world the results of some experiments by Mr. M. B. 



* Bailey, "The Survival of The Unlike," page 347. 



