122 HESSIAN FLY. 



It first showed itself in Long Island, from 

 whence it proceeded inland, at about the rate of 

 fifteen or twenty miles annually, and by the 

 year 1789, had reached two hundred miles from 

 its original station. I must observe, however, 

 that some accounts state its progress at first to 

 have been very slow, at the rate of about seven 

 miles per annum, and the damage inconsider- 

 able ; and that the wheat-crops were not mate- 

 rially injured by it before the year 1788. 

 Though these insect hordes traverse such a 

 tract of country in the course of the year, their 

 flights are not more than five or six feet at a 

 time. Nothing intercepts them in their de- 

 structive career, neither mountains nor the 

 broadest rivers. They were seen to cross the 

 Delaware like a cloud. The numbers of this 

 fly were so great, that in wheat harvest the 

 houses swarmed with them, to the extreme 

 annoyance of the inhabitants. They filled 

 every plate or vessel that was in use ; and 

 five hundred were counted in a single glass 

 tumbler exposed to them a few minutes, with a 

 little beer in it." This is Mr. Kirby's account ; 

 and an interesting description of the fly itself is 

 given by Mr. Curtis, in the papers previously 

 adverted to. We have only to hope this mis- 



