66 THE CHINCH BUG. 
It is feasible to eliminate both by simply smoothing off a path 
along the margin of an infested field where such a one adjoins the one 
to be protected. This can be done with a sharp hoe, and as the 
margins of wheat fields usually become compacted it is but little trou- 
ble to thus clear off a path a foot or more in width, smooth as a floor, 
with the surface almost as hard. - In the midst of this path post holes 
are sunk as in the bottoms of furrows, and a train of coal tar is run 
between them, being so arranged that it will reach the post hole near 
the inner side opposite the field from which the bugs are migrating. 
In this way as the bugs reach the train of coal tar they will follow 
along until they reach the post hole, while those meeting with the 
post holes will usually divide and, following around it, join with the 
flow of bugs moving along the train of coal tar. The result is that 
they become congested in the acute angle where the coal-tar train is 
intercepted by the post holes. Those in the apex of this angle can 
not turn back, and thus are continually pushed into the post holes by 
those behind. As the bugs, varying from the red larve to the 
almost black pupe, mass along the line of coal tar they have much the 
appearance of a reddish-brown stream running into the holes. From 
these holes there is no escape and here the bugs can be readily killed 
by sprinkling with kerosene. The shghtest train of coal tar is suffi- 
cient to obstruct the passage of the bugs, and light rains will not 
affect its efficiency. In dry weather these trains of coal tar soon be- 
come covered over with dust and must be renewed; but in showery 
weather there is no dust, and if the coal tar is renewed daily or, at 
most, twice each day it will accomplish its work and nothing further 
will be needed than to kill the bugs that have collected in the post 
holes. This measure is inexpensive and can be promptly put into 
operation if the coal tar is at hand. The writer has been able in this 
way to effectively protect a field of corn surrounded on two sides by 
a wheat field literally overrun with chinch bugs at harvest and during 
a time when light showers were occurring, frequently several times 
each day. 
THE RIDGE AND COAL-TAR METHOD. 
Differing quite materially from the preceding are the various com- 
binations of coal tar and ridges of earth, smoothed and packed along 
the apex, or, instead of the ridge of earth, 6-inch boards, such as 
are ordinarily used for fencing, placed on edge and the upper edge 
coated with tar. Forbes has reported excellent results from the ap- 
plication of a line of coal tar put directly upon the bare ground where 
the surface. has been rendered compact by a recent fall of rain. Even 
in this series of protective measures kerosene can be used to great 
advantage. In the experiment recorded by Professor Forbes the coal 
tar was put upon the ground between a wheat field and a cornfield 
