258* Insects Injurious to Vegetation. [Oct., 



the Hessian fly is destroyed." Another vahiable paper from Mr. 

 Herrick appears in the report of the Coinmissioner of Patents for 

 the year 1844, (p. 161-167,) giving a most exact and particular 

 history of the transformations of this insect, and a summary view 

 of the various remedial measures that have been proposed. Both 

 of these papers evince the close and patient investigation which the 

 writer had made, and the utmost carefulness in announcing no- 

 thing beyond what he had clearly ascertained. 



Dr. T. W. Harris's invaluable " report on the insects of Mas- 

 sachusetts injurious to vegetation " was also completed in 1841. 

 An excellent summary of all the leading facts pertaining to the 

 history of this species, is given in this work (p. 421-433,) and its 

 generic place, upon which point Mr. Herrick, Latreille and others 

 had intimated doubts, is correctly settled. 



The numerous agricultural periodicals of our country, abound 

 with notices of this insect, more or less extended and valuable. 

 To specify these notices in detail, at least as respects some of 

 these periodicals, would require a reference to almost every num- 

 ber issued. Wherever important facts are derived from these 

 sources, in the course of this essay, they are accompanied by a 

 particular acknowledgement in each instance: an additional re- 

 ference in this place, is therefore deemed unnecessary. 



We close this section of our subject, with a condensed view of 

 the depredations of this insect in the different parts of our coun- 

 try, during a few of the past years; the materials for which, are 

 furnished us, in those valuable documents, the yearly reports of 

 the Commissioner of Patents. 



In the year 1842, the ravages of the Hessian fly would appear 

 to have been quite limited. Pennsylvania suffered the most se- 

 verely. The wheat crop in this state is estimated to have been 

 twenty per cent less than it was the preceding year, and of four 

 different causes that produced this diminution, the fly is placed 

 first. Some parts of Maryland, and also of Ohio, were visited by 

 it. In the latter state, it appeared to be increasing so much, that 

 serious apprehensions were beginning to be felt respecting its fu- 

 ture ravages. 



