Sixth Annual Report. ’ 31 
_ July 8 Renewed tar on ridge. Bugs on ridge, but none going into the post- 
holes, except on southwest corner. 
July 9. A few bugs flying. 
July 10. Renewed the tar. Bugs quite lively on the ridge: some going into 
- the holes. 
_ July 12. Renewed tar. More bugs on the ridge than at any other time. To- - 
_ day made a new ridge, on the side marked 2, plate II. Before plowing the double 
f _ furrow we took the plow and turned a shallow furrow out, so as to cut off the sod 
_ from the ridge. This we found to be satisfactory. We did not use the shovel 
__ except in one spot where the plow would not work in the hard soil. Then we 
used tar mixed with different bad-smelling and offensive odors. On the part 
marked z, plate II, we used very offensive odor resembling that of skunks, phe- 
nyl isocyanide. About one gill was mixed with a bucket of tar. (A little of the 
__ cyanide was turned on to the ground ina line before the bugs, which caused them 
to stop at once, thus showing very clearly that it was the odor that stopped 
them.) On the part of the ridge marked x2 was placed a mixture of tar and pyre- 
dine, C;H¢N, about one-fourth of a gill with one-half bucket of tar. The ridge 
on the west side was next to the wall, about ten feet from it, and after we had 
done we found that we had bugs on both sides. Of course the greater number 
- number were next to the stubble. A barrier on the north end of the field was 
made in the following manner: The plowing was done, as on the east side, by 
throwing the sod out and turning up a double furrow. It was leveled off with a 
hoe. Then a line of tar was placed on the ridge. It was very hard to get an 
even and compact surface on account of the lumps of dirt, so that when the tar 
was applied the quantity was considerably greater per rod than when the barrier 
implement was used. On the northwest side a barrier was made by plowing deep 
furrows, and then, with a shovel or hoe, the corner was cut off next to the grass 
side. This was found to be quite laborious. Then we made a small groove near 
the top side of the ridge to hold the tar; then the tar was applied. Not much 
_ was needed, as the ground was very hard. It was an easy matter to put the tar 
out when the narrow groove was made, but where the ridge was smooth the tar 
would not stay in line, but ran down at the sides in a very small stream. 
July 13. Renewed the barrier on the ridge a. See plate II. Bugs very plen- 
% tiful on this ridge but none are crossing. In a number of holes there is water, 
out of which they are not able to crawl. On the new ridge, marked x, bugs are 
on both sides; although the tar is fresh and the cyanide is strong they are cross- 
ing back and forth. They seem to be confused, and to show a tendency to fol- 
low each other. On the ridge marked 22 the pyredine does not smell very strong. 
Renewed the barrier } on the north side, as it was not in as good shape as the 
ES ridge x. The dirt in drying fell away and cracked in a number of places. Bar- 
rier c, the one that was smooth, was renewed. The stream of tar that was put 
on was so small that it dried into the ground. Barrier d, the one with smooth 
side containing a groove, was full of dirt, so that it did practically no good. On 
none of the new barriers were bugs marching. Saw a few bugs flying to-day. 
; July 15. Bugs are very lively on the ridge and in very large quantities. They 
are not crossing the cyanide. Bugs on the wall or outside have disappeared. 
Cyanide quite strong on x. Could not smell the pyredine on x2. The parts d 
and d are in very’good shape. Onc the groove was filled with dirt again. Re- 
newed all barriers. 
July 17. More bugs on the ridges than on any day since the experiment com- 
menced; they are moving in great numbers and are being rapidly caught in the 
holes. Estimate those in the post-holes at one-half bushel each. While the 
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