10 
During the last two weeks of April a great many small lots of 
parasites were distributed over the southern and central countie: of 
Kansas by Mr. S. J. Hunter, of the Kansas State University. The 
artificial sending out of these parasites by Mr. Hunter and the test 
of distributing an enormous quantity in a single field, described 
above, were legitimate experiments, but the evidence showed very 
conclusively that they resulted in no benefit whatever. In other 
words, as noted above, the parasites were already infesting 12 per 
cent of the “ green bugs” at Wellington, Kans., April 9, when the 
artificial introduction was made, and 50 to 75 per cent at King- 
fisher, Okla., at the same date, and they were only waiting for weather 
conditions to make it possible for them to do their work. Just as 
soon as the favorable weather arrived the parasites bred enormously 
and quickly overcame the * green bug.” In no case was there a field 
of the hundreds examined in southern Kansas where the parasites 
natively present did not outnumber by many thousands or hundreds 
of thousands any number that could have been introduced artificially, 
at a time when weather conditions had become such that the hbera- 
tions could have had any benefit. As shown by the careful investiga- 
tions of the agents‘of this Bureau in the field, and independently of 
Prof. E. A. Popenoe, entomologist of the Kansas State Agricultural 
College, and his assistants, the parasites were equally abundant in all 
fields in May, when weather conditions became favorable, irrespective 
of whether distributions had been made or not. 
The weather, therefore, is the important influence. As demon- 
strated by the experience of this and other years, these parasites, 
always present in hmited numbers, will overcome the aphis unaided 
as soon as weather conditions permit, and no artificial introduction, 
great or small, appears to hasten or increase their efficiency. 
The writer left Washington for Kansas May 13 to take personal 
charge of the field work in relation to the * green bug” and to make 
a thorough survey of actual field conditions. The “ green bug” at 
this time (May 15) had become abundant in oats as far north as 
Manhattan, Kans.; but wherever present there were numbers of 
parasites also already in evidence. Indeed, Mr. Phillips found this 
to be true at Kearney, Nebr., which point he visited about a week 
later. In no instance was a field observed, either in-the vicinity of 
Manhattan or, during the next week or ten days, anywhere in Kan- 
sas, Where the parasite was not present wherever the “ green bug” 
occurred. 
A further experiment, this time tried for the purpose of testing the 
possibility of hastening the work of-the parasite during favorable 
weather by large introductions, was carried out as follows: The sub- 
jects of the experiment were two fields of oats, each containing 4 
~ 
[Cir. 93) 
