106 JOURNAL OF ECONOMIC ENTOiMOLOGY [Vol. 5 



modification of these conditions in southern Michigan and north- 

 western Ohio. The influences of Lake Michigan and Lake Erie exert 

 a very considerable influence on the appearance of the fall brood of 

 Hessian fly. As a matter of fact, the farmer in Michigan, as far north 

 as Lansing at least, can sow his wheat no earlier than can the farmer 

 a considerable distance south of the Ohio line. 



We have on record results of wheat sowings made in northern New 

 York in co-operation with the New York Experiment Station, south- 

 ward into South Carolina, where we worked in co-operation with the 

 Agricultural Experiment Station at Clemson College. West of the 

 Alleghany mountains we have the record of a series of wheat sowings 

 made in extreme northern Michigan where Hessian fly does not occur, 

 southward to central Georgia where our experiments were carried 

 out in co-operation with the state entomologist. Besides these we 

 have a vast amount of information obtained by myself and the men 

 working under my direction throughout northern Indiana. 



This mass of material is awaiting the completion of some other work 

 on this species before being published. Not only do I think Doctor 

 Headlee correct in his statements, but I would even go farther and 

 strongly suggest that the absence of Hessian fly in some parts of the 

 country is due to these same influences. 



When Hessian fly was destructively abundant at Great Bend, Kan- 

 sas, it required an expert to detect its presence at Dodge City where 

 wheat is grown throughout and beyond this area and has been for the 

 last 25 or 30 years. When wheat is ruined by Hessian fly in Sumner 

 County, southern Kansas, 20 miles south of Arkansas river in Okla- 

 homa, a good entomologist may find one or two individuals for each 

 hour's search. 



There is a great deal of work to be done on this problem, and while 

 government entomologists can work over an area embracing a half 

 dozen states, we do not have either the time or the men to work out 

 problems as carefully within the boundaries of a single state as Doctor 

 Headlee is able to do. 



There is another point that always presents itself in connection 

 with these Hessian fly problems. The effect of rainfall on the emer- 

 gence of Hessian fly in autumn is pretty well known, but there are so 

 many other factors entering into the problem of evading Hessian fly 

 attack that the farmer gets befuddled and is likely to disregard all, 

 or a great deal, of advice given him. A good farmer will often raise 

 a crop of wheat side by side with a neighbor who loses his by Hessian 

 fly attack, so that there comes a point where the question ceases to 

 be an entomological one and becomes strictly agricultural. 



Another thing, in the East we never find Hessian fly breeding in 



