34 
was begun, infesting a strip about thirty yards in length and seven 
or eight rows deep. 
To prevent the further entrance of chinch-bugs into these three 
corn fields from without, 1080 yards (about three fifths of a mile) 
of impassable barriers were required, with approximately 160 
post-hole traps distributed along them ; and to destroy those already 
in the field before our work began it was necessary to spray a part 
of the northwest field with kerosene emulsion. 
When these premises were taken in charge for our purpose by 
Mr. Taylor, June 23, 1904, the wheat was already nearly ripe, and 
harvesting began a few days later, continuing until July 7. The 
chinch-bugs were at first by no means hurried in their movement 
out of the wheat, as there were still grassy weeds in the stubble to 
detain them, and the frequent showers of the following month kept 
this vegetation in good condition continuously. The movement 
towards the corn was well marked, however, from the beginning, and 
prompt measures were necessary to protect that crop. There was 
also urgent need for a destruction of chinch-bugs already in the 
corn, and this was the first task undertaken, kerosene emulsion being 
made up to June 23 in a rather rough-and-ready manner by stirring 
the kerosene and soap-suds together vigorously for several minutes 
with a stick. This mixture was then flirted on to the corn with the 
naked hand at a rate of about a pint to every three hills. The first 
mixture contained five per cent, of kerosene, and was evidently too 
crudely made, proving injurious to the corn, especially where it was 
held in the conical cavity formed by the terminal tuft of leaves. It 
was estimated that about twenty-five per cent, of the stalks treated 
on this first date were damaged more or less. A four per cent, mix- 
ture, on the other hand, as applied on the 24th of June, did no dam - 
age to the plants, and is reported to have killed the chinch-bugs as 
soon as it touched them. This emulsion was used from time to 
time thoroughout the whole period of the experiment in parts of 
two fields of corn where the bugs made their way around the ends 
of the barriers in number to require special measures for their de- 
struction. 
An effort was made at the very first to use a dusty furrow as a 
barrier, with post-holes dug in the bottom to trap the bugs, and 
about one hundred and sixty rods of such furrows were made June 
23 to 25 on the eastern and southern sides of the northwest field, 
and on the west side of the four-acre patch. The ground was deeply 
plowed and thoroughly harrowed in a four-foot strip, and a ridge 
was formed by making a back furrow down the middle. A log was 
then dragged through the center of the strip until a dusty groove 
