13 
saying that the greater was the damage, the larger was the 
area in crops of any and all kinds capable of furnishing food to 
chinch bugs*. 
This conclusion clearly compels at once a reconsideration of the 
effect of wheat alone,—a re-examination of the table so made as to 
ascertain whether the wheat area increases faster with increased 
injury than does the area in the other crops reported. On this 
point the indications of the table are not quite clear, but are 
nevertheless interesting and suggestive. The increase in wheat 
corresponding to the five available numbers of the table we find 
to amount to an average of 31 per cent, for each step of the 
gradation; while that of corn amounts to only 8 per cent.; that of 
grass to 10 per cent.; and that of oats to 33 per cent.; in other 
words, while wheat and oats have increased in about the same 
ratio with increase of injury by chinch bugs, and bear, so far as 
this table is concerned, the same relation to such increase, the 
corresponding increase of corn has amounted to only about one 
fourth that of the wheat, and the grass increase to about one third. 
Prom this we are certainly justified in concluding, provisionally, 
that, even under the extreme conditions prevailing in Southern 
Illinois last year, the acreage of wlmat has more to do with the 
increase of chinch-bug injury to corn than the area of any other 
crop, except, perhaps, oats; but as the latter crop, and also corn 
and grass, seem also to favor insect increase, we find little en¬ 
couragement for the supposition that under such circumstances an 
abandonment of wheat alone will serve to control injury by the 
chinch bug, or seriously to check its increase. 
Table II. 
Central Illinois , 397 Towns. Injury to Corn , 1887 , compared 
with Crop Areas for the Same Year. 
Degree of Injury. 
No. 
of Tps. 
Wheat. 
• 
Barley. 
Kye. 
Oats. 
Corn. 
Grass. 
None. 
244 
1,311 
1 
98 
2,754 
5,765 
5,992 
Little. 
73 
2,080 
1 
44 
2,281 
5,045 
5,439 
Moderate. 
14 
2,368 
5 
31 
1,711 
4, 488 
4,880 
flnnsiderahlo . 
33 
2,582 
16 
1,172 
3, 275 
4,338 
Great . 
8 
2,641 
23 
1,502 
3,003 
5,331 
Very great,. 
11 
2,949 
45 
2,134 
4,514 
5,154 
Nearly complete. 
13 
3,189 
27 
2,254 
4,428 
6,017 
Complete. 
1 
6,113 
317 
4’257 
7,251 
11,616 
Passing now to Table II., for 397 towns of Central Illinois 
where all the grades of injury to corn except the highest are rep¬ 
resented by groups of townships sufficiently large to be available 
*As it here seemed possible that the larger area under cultivation was a consequence of the 
greater and long-continued chinch bus injury with which I found it associated, and not in any 
sense a cause,—due, in fact, to the clearing up of the richer bottom lands in Southern Illinois, 
where the partially exhausted prairie lands had repeatedly failed to yield a profitable crop,—I 
’thoroughly overhauled my data with this point in mind, but without finding any ground for such 
a conclusion. The area under cultivation in the principal crops was greater in 1887 than in 1886, 
but the increase was not more marked in regions badly infested than in those where the damage 
was lees. 
