1846.] Insects Injurious to Vegetation. 245 



that has been assigned to this species. Our scientific journals, 

 our agricultural magazines, and our common newspapers, have 

 each accorded to it a conspicuous place in their columns. As 

 may well be supposed, almost every point in its history, has by 

 one and another of its observers, been closely investigated, and 

 laid before the public. Very little that is new, can therefore at 

 this day be embodied in an account of this species. The most 

 that an observer can accomplish, is to add his testimony in con- 

 firmation of facts that have been already announced. The most 

 that a writer can aim at, is to gather the various papers that are 

 scattered through volumes suflficiently numerous of themselves to 

 form a library, sift from them w^hatever they contain of impor- 

 tance, and arrange the facts thus acquired, into a connected and 

 symmetrical memoir. Such is the object of the present essay; to 

 carefully review the various accounts that have been hitherto 

 published, extract from each the items of value which it contains, 

 compare these with personal observations made under favorable 

 circumstances during the past twelve months, and with the mate- 

 rials thus acquired, w^rite out a history of this species, more am- 

 ple in its details than any that has been hitherto attempted, and 

 containing a complete summary of all that is known of this in- 

 sect down to the present day. 



It is a European Insect. 



For several years subsequent to the first appearance of the 

 Hessian fly in this country, it was universally believed to have 

 been derived from abroad. When, however, the severe devasta- 

 tions which it was committing upon this continent became known 

 in Europe, public attention was so strongly excited as to lead to 

 an extensive and thorough search for the insect there. The result 

 of this investigation, as given by Sir Joseph Banks in his report 

 to the British government, was, that " no such insect could be 

 found to exist in Germany or any other part of Europe." It M^as 

 in consequence, received as an established fact, and assented to 

 on all hands, that this was an exclusively American species. Of 

 late years, however, new light has been shed upon this subject; 



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