352 BOARD OF AGRICULTURE. 



live without purpose, are really, though few realize it, among 

 the best friends and allies of man. 



Moreover, insects are of great use as scavengers, such as the 

 young or maggots of the house fly, the mosquitoes, and numer- 

 ous other forms, that seem created only to vex us when in the 

 winged state. Still a larger proportion of insects are directly 

 ])eneficial from their habit of attacking injurious species, such 

 as the ichneumons, or parasitic hymenoptera, and certain para- 

 sitic flies, allied to the house fly, and many carnivorous species 

 (wasps, beetles and flies, dragon flies and Aphis lions, etc.) that 

 live upon other insects. 



But few, however, suspect how enormous are the losses to 

 croi)S in this country entailed by the attacks of the injurious 

 species. In Europe, the subject of applied entomology has always 

 attracted a great deal of attention. Most sumptuous works, 

 elegant quartos prepared by naturalists known the world over, 

 and published at government expense, together with smaller 

 treatises, have frequently appeared ; while the subject is taught 

 in the numerous agricultural colleges and schools, especially of 

 Germany. 



In the densely populated countries of Europe, the losses 

 occasioned by injurious insects are most severely felt, though 

 from many causes, such as the greater abundance of their insect 

 parasites, and the far greater care taken by the people to exter- 

 minate their insect enemies, they have not proved so destructive 

 as in our own land. 



Ill this connection I might quote from one of Dr. Asa Pitch's 

 reports on the noxious insects of New York, where he says : " I 

 find that in our wheat-fields here, the midge formed 59 per cent, 

 of all the insects on this grain the past summer ; whilst in 

 France, the preceding summer, only 7 per cent, of the insects 

 on wheat were of this species. In France, the parasitic de- 

 stroyers amounted to 85 per cent. ; while in this country our 

 parasites form only 10 per cent." 



As the writer lias already remarked in the current volume of 

 the American Naturalist, "a true knowledge of practical ento- 

 mology may well be said to be in its infancy, when, as is well 

 known to agriculturists, the cultivation of wlieat has almost been 

 given up in New England, New York, Pennsylvania, Ohio and 

 Virginia, from the attacks of the wheat midge, Hessian fly, joint 



