OUTBREAKS IN NORTHWEST. 13 
OUTBREAKS IN SPRING- WHEAT REGIONS IN NORTHWESTERN STATES. 
In 1896 there was a considerable outbreak of the Hessian fly in the 
spring-wheat region of northern Iowa, southern .Minnesota, and prob- 
ably a part of South Dakota. Professor Lugger (69) in Minnesota and 
the writer (89) in Iowa called attention to these occurrences in bulletins 
on the insect outbreaks of the year, and both noted the great abundance 
of parasites in the material received. The presence of the latter pre- 
cluded the rearing of adults, but the characteristics of the attack, the 
distinctive features of the larvae and puparia, and the fact that the 
typical parasites of the Hessian fly were reared leaves no question as 
to the species. 
In the summer of 1897 the writer traveled over a considerable part 
of northwest Iowa and touched on southwestern Minnesota and eastern 
South Dakota with a view to examining the extent of injury, nature 
of the attacks, and so far as possible to study the conditions affecting 
the Hessian-fly outbreaks in this region. In nearly all the localities 
visited the injuries of the previous year had not been repeated, or 
the insect was present in such limited numbers as to cause very little 
damage and attract no attention from farmers. 
In a number of the fields in the vicinity of Alta and Storm Lake, in 
Buena Vista County, there was a small percentage of injury, possibly 
1 to 2 per cent, it being possible to find occasional stalks of wheat 
broken down in the manner characteristic of the Hessian ti}' and with 
larvae or puparia in the usual position under the leaf sheath. 
On farms where the year before there had been considerable injury 
and the crop had, following my suggestion, been early plowed under, 
there was no trace of Hessian fly even in large fields. 
In Lyon County farmers stated that there had been injury in 1896, 
their description of the injury leaving scarcely a doubt as to the author, 
but no traces of Hessian fly were to be found during my stay in the 
count}-. I was informed that in the vicinity of Sioux Falls, S. Dak., 
there were several farms that had suffered the year previous, but here. 
too, I could find no evidences of the presence of the insect, nor could 1 
hear of any injury for the season of 1897. 
Examinations of fields in the vicinity of Cherokee, and Sioux City. 
Iowa, and Yankton, S. Dak., resulted in finding no infested fields, nor 
did I learn of any serious injury from Hessian fly theretofore. 
A little later in the season (July 30), I received word from Mr. 11. E. 
Crosby, Alta, Iowa, that he had examined several tields in that vicinity 
and found but few in which the insect was not present. Without 
stating definitely the extent of the damage, he leaves me to infer that 
the amount of injury was about the same as noted at the time I was 
there. I also received a communication from Mr. M. A. Marley, oi' 
River Sioux, in Harrison County, close to the Missouri River, contain- 
ing reports of injuries in the wheat tields at that point and from his 
description there was evidently a greater amount of damage than in 
