142 
Over the northern part of the country where the insect passes the 
winter largely or wholly in the egg state, another measure can be 
applied to great advantage. The junior author has found that blue 
grass (Poa) is not only a summer food plant, but that it is very largely 
upon this grass that the eggs are deposited in the fall, and from 
which the offspring of the stem mothers make their way to the grain 
fields in spring. He has observed cases where the portion of a grain 
field bordered by bluegrass was the most seriously affected part of 
the entire field. If, then, roadsides, fence corners, and other waste 
lands were closely grazed in fall, winter, or early spring, these eggs 
would be largely destroyed and the food supply of the stem mother 
and her progeny cut off. This can always best be done during mild 
winters on account of a lack of snow. Where close pasturing is not 
practicable, burning over during the same season will have a similar 
if not an even more drastic effect. 
ARTIFICIAL INTRODUCTION OF PARASITES. 
As ApJiidius testaceipes destroyed such hordes of Toxoptera in 
apparently very short periods of time, after they had once become 
established, we thought it possible materially to aid in this destruc- 
tion by introducing the parasites artifically into localities where they 
were apparently absent. As Mr. C. N. Ainslie was unable to find 
any evidence of parasitization in the fields about Wellington, Kans., 
on April 1, 1907, it was decided to begin operations there. Accord- 
ingly, on April 9, over a bushel of wheat leaves that were almost 
covered with parasitized Toxoptera were collected at Kingfisher, 
Okla. Mr. Ainslie took charge of this material, and on April 10, made 
a careful survey of the fields about Wellington, Kans., to determine 
the situation relative to Toxoptera infestation, and on the morning 
of April 1 1 he scattered a portion of this material in one of the most 
badly infested fields that could be found in that vicinity, the remain- 
der being left sheltered by the box lids. At this time he could find 
parasitized Toxoptera already in the fields, both the dead leathery 
bodies and those showing the characteristic yellow color. The 
parasites included in this introduction were roughly estimated at 
2,500,000; this number, however, was probably not a "drop in the 
bucket " to those already in the field. If there were only one or two para- 
sitized Toxoptera to a leaf, when a whole field is considered 2,500,000 
would seem to be a very small number. So far as published records 
show this was the first artificial introduction of parasites into Kansas. 
April 12 another lot of parasitized material, sent Mr. Ainslie by 
the junior author from Kingfisher, which was fully as large as the 
previous consignment, was introduced into another field 2 miles 
from the first. All of this material, originally intended for one field, 
was reported as one experiment by the junior author and appeared 
as one experiment in Circular 93, since Mr. Ainslie's notes were not 
on file in the office at the time. We find, however, that Mr. Ainslie, 
