On the Hessian Fly, 149 



3d. They changed from the caterpillar state the latter 

 end of Mav and beginning of Jane ; and 



4th. The fly came out of the chrysalis the latter end 

 of July and beginning of August, and deposited their 

 eggs the latter end of August and forepart of September. 



Second generation, 



1st. The esrgs were laid the latter end of August, and 

 in September to the 20th. 



. 2d. In a few days the eggs were hatched, and the 

 caterpillar appeared in September. 



3d. They changed from the caterpillar to the chrysalis 

 state in October, in which state they continued the suc- 

 ceeding winter. 



1797. 4th. The fly left the chrysalis state, and ap- 

 peared in the latter end of April and forepart of May. 



Having thus marked the progress of these insects 

 through their various transformations and economy for one 

 year, and pointed out the manner in which they destroy 

 the young plants of wheat, from thence we will endeavour 

 to draw some conclusions, whereby we may he led to a 

 remedy to prevent their pernicious effects. These ap**^ 

 pears to be, 



1st. To guard against their destroying the young plants 

 in the autumn. 



2d, To guard against their destroying the plants in 

 the spring. 



The first intention can be accomplished only, by not 

 so\^ ing until the period of laying their eggs is past, before 

 the young plants appear in leaf. 



It appears the flies have generally done laying their 

 eggs by the 20th of September, but as this point is of 



Cc 



