13 
The furrow beside the first row did not check their advance 
to a very great degree, from the fact that it had been de¬ 
faced and broken down to some extent, and was strewn with straw 
and other rubbish from the wheat. The furrow beside the fifth 
row and tar line by the sixth, however, completely arrested their 
advance and practically kept them confined to the first five rows, 
where a quart or more could have been easily collected in a few 
minutes by jarring the stalks and catching the bugs in a pan. 
The insects worked away in the furrow, endeavoring to escape much 
as described under experiments 1 and 2. An occasional one made 
good its escape by means of a projecting rootlet or the rubbish 
strewn about, but was repelled by the tar line in the next 
row, which seemed to be regarded as an impassable obstacle. In 
both cases there was a general movement up and down the lines, 
and the bugs were constantly falling into the post-holes, a pint or 
more being entrapped in each, where they were killed with a 
strong mixture of kerosene and water or by a little coal-tar poured 
upon them. 
In the furrows where the bugs were directly exposed to the snn, 
a great many were killed by the extreme heat, the tender larvse- 
succumbing first, but even adults dying finally. 
These furrows were dressed up here and there from day to day 
with a hoe, as was necessary, and the tar line was renewed about 
every twenty-four hours. A slight rain fell July 13, just enough 
to lay the dust, and the furrow in the fifth row no longer re¬ 
strained the marching horde. The ground was covered with 
young bugs, either in the pupa stage or the moult just preceding, 
and their advance was southward toward the center of the field. 
The tar line, however, remained unaffected, and proved the same im¬ 
passable barrier to the advancing hosts as when first put down. The 
bugs ran restlessly up and down the tar front, tumbling into the 
post-holes, where they were finally destroyed, or being speedily 
killed in the furrows by the excessive heat as they ran here and 
there over the ground. 
The insects made good their advance in the eastern half of the 
field, where no barriers obstructed their course, and completely- 
covered the corn as far as the ninth and tenth rows inward. The 
average yield in such places was reported at the end of the sea¬ 
son by the farm superintendent as about twenty per cent, less 
than that of corresponding rows in the upper part of the field, 
where the barriers had been used. The chinch-bugs, on the other 
hand, were originally far less numerous in the wheat adjacent to- 
this part of the field than at the other end, where they were de¬ 
stroyed as described above. 
The five following (Nos. 7-11) are farmers’ barrier experiments, 
made to arrest the advance of chinch-bugs as they moved from 
wheat to corn in late June and early July. 
No. 7. Made by Mr. Samuel Bartley, of Edgewood. A narrow 
strip of ground in corn along the side adjoining wdieat was deeply 
