I have selected, first, for examination the relation between: 
injury by chinch bugs to corn in 1887, and acreage in wheat 
and other grains for the same year. As the chinch bugs bred in wheat 
in spring resort finally to corn, and rear there almost exclusively the 
second brood of the season, we should expect to find any increase 
in chinch bugs due to a large wheat acreage, expressed in a larger 
degree of damage to corn in the same territory. Examining first 
the table for Southern Illinois and throwing out the first three 
groups of townships because too small to give an average of any 
value, we observe a slightly irregular but unmistakable increase 
in average wheat acreage as the chinch-bug injury to corn in¬ 
creases. Seven towns reporting the injury to corn as “consider¬ 
able,” have a wheat area of 1,905 acres each, while twenty-eight 
towns where the corn was totally destroyed averaged two and a 
fourth times as much—4,266 acres each. The intermediate num¬ 
bers form an ascending series, except that the second one is un¬ 
duly high, but still below the last. This plainly shows that in 
Southern Illinois, in 1887, the wheat area was much greater, on 
the whole, where the damage to corn by chinch bugs was the 
greater, and greatest of all where the destruction was complete. 
Immediately, however, an interesting and important question 
arises. Is it not possible that in these towns less corn was raised 
where there was more wheat, the area in the two crops varying 
inversely, the great chinch-bug injury to corn apparent being then 
due to the smaller corn acreage, and the consequent closer con¬ 
centration of insects in what corn there was? 
The column headed “corn” in the same table gives the answer to 
this question, and from this we learn that the corn area did not 
decrease as the wheat area enlarged, but that, on the contrary, it 
actually increased (though irregularly) as the wheat did.* Cer¬ 
tainly, therefore, the corn was not more injured only because there 
was less of it. 
That the corn acreage should increase with chinch-bug in¬ 
jury to the crop is a surprising fact, and suggests a glance at 
the columns for oats and grass (barley and rye being insignificant 
crops in Southern Illinois), and here we learn that the area in 
these two great staples also was the greater^ where chinch bugs 
were the more abundant,—the increase in the numbers for these 
crops being an almost continuous one from 1,114 to 2,671 for oats and 
from 2,121 to 2,975 for grass. We reach, consequently, the interesting 
and unexpected generalization that where the destruction of corn 
by chinch bugs in the southern part of the State was greater, 
the area was greater in wheat, oats, corn, and grass,—that is in the 
staple farm products of the region. This is little more than 
*The first two numbers in this series of five amount to 5,476 and the last to 6,016. 
