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34 THE SPRING GRAIN-APHIS OR GREEN BUG. 



north and south. This area was investigated by Mr. Ainslie on the 

 23d of May. There was plenty of evidence of Toxoptera attack. 

 Some fields were killed outright and others badly spotted, but a 

 number of fields were little injured. No particular reason could be 

 assigned for this condition of the fields, and this area, with a few 

 interruptions, extended on to the west indefinitely. This belt extend- 

 ing across the wheat-growing section of Oklahoma was evidently 

 observed by Mr. Sanborn, who stated in his notes, copies of which 

 were furnished by Prof. Conradi, under date of March 29, 1907, 

 "Northern boundary of parasitized infestation is between Kingfisher 

 and Enid." Again, under date of March 30, "Pondcreek, Okla. 

 Doing great damage, in large spots, here. There lies a peculiar fea- 

 ture between this and Kingfisher. At these two points the infestation 

 was about equal. Enid has no damage yet." 



Mr. Ainslie now started northward to trace Toxoptera to its most 

 northerly point in the United States and to learn to what extent its 

 parasite occurred with it, stopping at the following places : Kingman, 

 Kingman County, Kans.; Hutchinson, Reno County, Kans.; Sterling, 

 Rice County, Kans.; Scott, Scott County, Kans.; Great Bend, Barton 

 County, Kans.; Oakley, Logan County, Kans.; Colby, Thomas 

 County, Kans.; Goodland, Sherman County, Kans.; Manhattan, Riley 

 County, Kans. ; Lincoln, Lancaster County, Nebr. ; Plainview, Pierce 

 County, Nebr.; Dixon, Dixon County, Nebr.; Sheldon, O'Brien 

 County, Iowa; Mason City, Cerro Gordo County, Iowa; Dodge Center, 

 Dodge County, Minn. ; Rochester, Olmsted County, Minn. ; Brookings, 

 Brookings County, S. Dak.; Aberdeen, Brown County, S. Dak.; 

 Fargo, Cass County, N. Dak. ; East Grand Forks, Polk County, Minn. ; 

 Hallock, Kitson County, Minn.; Grafton and Park River, Walsh 

 County, N. Dak.; Larimore, Grand Forks County, N. Dak.; and 

 Casselton, Cass County, N. Dak. He reached the last-mentioned 

 place on August 5, a£ter which he returned to Washington, D. C. 



Except at Kingman, Hutchinson, Sterling, Great Bend, and Man- 

 hattan, Kans., Mr. Ainslie found but little damage resulting from 

 Toxoptera, the most striking feature being the fact that parasites 

 were found associated with Toxoptera at each point visited with the 

 following exceptions: Goodland, Kans., very few Toxoptera in this 

 immediate vicinity; Lincoln, Nebr., no Toxoptera found; Brookings, 

 S. Dak., 2 to 3 Toxoptera only seen; Aberdeen, S. Dak., no Toxoptera 

 found; Fergus Falls, Minn., only 1 Toxoptera observed here. The 

 significant feature of this is that no parasites were introduced artifi- 

 cially at any of these points outside of Kansas. 



From statements made by Prof. J. M. Stedman, who was professor 

 of entomology at the University of Missouri at this time, it appears 

 that Toxoptera was swept over the border from Oklahoma and Kansas 

 into southwestern Missouri. Prof. Stedman states that there were 

 from six to eight counties in the southwestern corner that were very 



