28 YALE AGRICULTURAL LECTURES. 



wheat fields were destroyed, and its ravages usually continued 

 for several years, or until its parasitic enemies had multiplied 

 sufficiently to subdue it. It has frequently reappeared here 

 and there, but for many years now, little has been heard of it. 

 This is probably the same insect that is mentioned by Duhamel 

 as having greatly injured the wheat in Switzerland in 1732, and 

 again in 1755 ; but during the half century of its worst ravages 

 here, it lurked undetected in Europe, till in 1833 it ravaged 

 a part of Germany, and in 1834 was found by Prof. Dana along 

 the Mediterranean in every wheat field he visited in Spain, 

 Italy, and on the Island of Minorca ; and finally, in 1852, much 

 damage was caused by it upon the River Volga, where its 

 parasite was also found accompanying it. Such is, in brief, all 

 that is known of the European history of this insect, which, 

 introduced upon our side of the Atlantic, has caused a loss of 

 uncounted millions of dollars. 



The wheat midge has long been known in England. It was 

 originally supposed to be a sort of mildew which thus blighted 

 the wheat, and was only ascertained to be an insect in 1771. 

 And in 1797, Mr. Kirby, searching for the Hessian fly, partially 

 traced out the habits of this insect. It was doubtless intro 

 duced into this country in some unthreshed wheat brought to 

 Canada, for it was first noticed upon the St. Lawrence, and 

 also in Northern Vermont, in the year 1830, though it did not 

 multiply and become so destructive as to attract public notice 

 until nine years later, when it also began to extend itself, and 

 has now overspread Canada and all the Northern States as flu- 

 west as into Indiana. Its larva is a minute footless worm, or 

 maggot, of a bright orange-yellow color, found in numbers upon 

 the young kernels in the wheat heads, causing them to be small 

 and shrivelled, to such an extent some years that many fields 

 are not harvested, every kernel being blighted. In England 

 the midge is preyed upon by a parasitic insect, a small kind of 

 ichneumon fly, which rapidly multiplies whenever the midge 

 becomes numerous, and thus quells and subdues it, just as the 



