34 THE SPRING GRAIN-APHIS OR 
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, after 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 
