126 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



fall will delay the appearance of the flies, even with normal tem- 

 perature conditions, and the further south, the later they appear. 

 From experiments being conducted by the V. S. Bureau of Ento- 

 mology, Professor F. M.Webster states that the following dates will 

 probably be found safe for sowing wheat in average seasons: in 



FIG. 92. "Flax-seeds" or puparia of the Hessian fly on young wheat 

 enlarged. (After Pettit.) 



northern Michigan soon after the 1st of September; in southern 

 Michigan and northern Ohio, about September 20th; in southern 

 Ohio after the first week in October; in Kentucky and Tennessee, 

 October 10th to 20th; in Georgia and South Carolina, October 



