143] 



Sotne Observations on the Hessian Fly ; tvritten m the 

 year 1797. By Dr. Isaac Chapman. 



Read x\ugust 14th, 1820. 



This insect first appeared in Bucks county in the 

 spring of the year 1786, upon the banks of the Delaware 

 opposite Trenton, having crossed the river from New 

 Jersey, where it had the preceding year destroyed the 

 greatest part of the wheat ; but in Bucks not much da- 

 mage was observed except in a few fields opposite Tren- 

 ton. After harvest they spread over several townships, 

 and the farmers having sown their wheat the latter end 

 of August and beginning of September, the young plants 

 in two or three weeks after appearing above ground be- 

 gan to die, and when winter came on, instead of the 

 ground being spread over with verdure, as it used to be, 

 in many fields the young plants were nearly all destroyed 

 by the insect. 



In 1787 the wheat was, in several townships, the 

 greatest part destroyed. After harvest they spread to a 

 great extent, and did great injury to the young wheat 

 before the frosts appeared. 



In 1788, in the beginning of May, and until the 15th 

 or 20th of the same, many fields appeared very promising, 

 but then the growth of the wheat began to be at a stand, 

 and after some days withered and died ; many farmers 

 seeing it thus withering away, turned their creatures into 

 the wheat fields, so that at harvest but litde had this year 

 come to maturity. After harvest they spread nearly all 

 over the county, and into some parts of the adjacent 

 counties of Philadelphia and Montgomery. 



The farmers observing in the two preceding harvests, 

 the wheat that had been sown early in the season to be 



