68 THE CHINCH BUG. 
The chinch bugs falling into this will be forced down by the weight 
of those coming after, and thus all will be passed through the kero- 
sene into the water below. This will obviate the necessity of fre- 
quently emptying the cans or treating their contents. It may also 
be stated that where the post holes are quite deep and enlarged at 
the bottom the bugs falling into them will perish without further 
attention. 
OTHER BARRIER METHODS. 
Professor Snow, working in Kansas, followed a somewhat different 
method and one that, under certain conditions, might be found supe- 
rior to that used by Professor Forbes, or the furrow and kerosene 
method applied by the writer in Ohio. This modification consists in 
throwing up a double furrow, known among farmers as “ back fur- 
rowing,” and thus forming a ridge, the top of which is smoothed 
and packed with a drag hawing a concave bottom of the form of the 
ridge to be made. If the bottom of this drag is covered with zinc, it 
will be found to keep bright and polished and by this means make 
a smoother ridge. The substances used were coal tar as it came 
from the gas works and crude petroleum as taken from the oil wells. 
The former is the more easily obtained, except in certain localities, 
and will probably be found the more practical, as it stands on the 
surface better and is not so readily washed away by rains. Both of 
these substances are, however, offensive to the bugs, and they will 
seldom attempt to cross them or even come close enough to touch 
them, but on approaching will turn and run along the ridge in the 
evident hope of finding a gap through which they can pass. Post 
holes were dug on the outside of the line, but close up to it, so that 
the bugs in passing along beside the tar line would crowd each other 
into them. Professor Snow suggests that it will be better to con- 
struct this barrier several weeks prior to its being needed, as then the 
tar line has but to be run along the ridge and the post holes dug, when 
the whole system is complete and the chinch bugs can be thus shut 
out from the first. 
With these barriers of either ridge or furrow and the use of coal 
tar or crude petroleum, supplemented by kerosene emulsion, a very 
large percentage of the injury from chinch bugs may be prevented, 
and, in fact, with a reasonable degree of watchfulness and prompt ac- 
tion, all injury from migrating hordes may be prevented. The use of 
tarred boards set on edge or slightly reclining might, under some 
circumstances, take the place of the ridge or furrow, but these cases 
will be exceptional, and the use of kerosene emulsion will probably 
a Fifth annual Report of the Director of the Experimental Station of the Uni- 
versity of Kansas, for the year 1895 (1896), pp. 45-47, 
