150 On the Hessian Fly, 



the greatest importance, more observations should be 

 made, and it should be determined with the greatest 

 accuracy, as on putting in the grain so early that the 

 plants may have a good root in the autumn, be enabled 

 to stand the winter, and begin to shoot up the stalk early 

 in the spring, depends gready the succeeding crop : and 

 yet it is necessary that it be sown so late, that the flies 

 cannot deposit their eggs on the leaves, and as this insect 

 appears on many occasions to be endowed with a won- 

 derful degree of instinct, so it appears by this unerring 

 instinct they are directed when is the proper time to de- 

 posit their eggs, which I think will be found nearly the 

 same every autumn. 



iVlthongh I have fixed the 18th or 20th of Septem- 

 ber as the latest period of depositing their eggs, after 

 which time I think few are laid, we will suppose it the 

 20th, then if the seed be sown about the 20th, all danger 

 from the insect in the autumn will be avoided, as it will 

 be several days before the young plants will appear above 

 trround. 



o 



2d. To guard against their destroying the plants in 

 the spring. 



Various things are necessary to be attended to, in order 

 to accomplish this intention. 



1st. The state, nature, and situation of the ground. 



2d. The variety of seed wheat sown. 



3d. The time of sowing. 



1st. It is found that wheat sown on ground that is 

 situated low, sheltered, and of a wet quality, is much 

 more damaged than that on land situated higher, more 

 exposed and of a dryer quality ; therefore the highest 

 and dryest ground on a farm should be chosen for sow- 

 ing wheat, and the land should be well cultivated, that 

 the young plants may have a quipk growth in the au- 



