* 
16 
part of the State, where the wheat acreage was large and the in¬ 
jury very severe, dominates the lower part of the table, the groups 
of townships representing the three higher grades of injury, being 
mostly in that section ;* while the upper part of this general table 
is little but a copy of the corresponding part of that for Central 
Illinois, the averages drawn from the relatively large wheat acre¬ 
age there being little affected by the very small wheat acreage of 
the northern district. Table IY. is, therefore, less an average of 
the others than a summary recapitulation of their teaching. The 
descending series presented by the six upper figures of the columns 
for rye, oats, corn, and grass remind us that a diminishing area 
of these crops goes with the increasing wheat areas of the first 
column, but that the decrease of the former is insignificant in 
comparison with the rate of increase of the latter;f while the 
regular rise in the lower numbers in each column simply expresses 
anew the fact that where the chinch bug has been long enough 
abundant to practically occupy the country, it will multiply accord¬ 
ing to the area in any and all crops capable of affording it food. 
In other words, these tables show us that corn suffered worst, as 
a rule, in 18S7, in those counties and townships where wheat was 
most abundant, and that a regular gradation of injury to corn by 
the chinch bug may be made out corresponding to the gradation 
in the wheat acreage; and, further, we learn that where the chinch 
bug became very numerous, the other great grass crops,—that is, 
the other small grains, corn, and the grass forage plants,—began to 
suffer heavily, to breed the first generation of the bugs, and so to 
encourage their increase and the consequent damage to corn—oatsi 
being the first to take this turn, and corn and grass the next. 
From these tables we may draw, then, this provisional practical 
conclusion, to be tested by the remaining tables of the series, 
that a limitation or abandonment of wheat culture may be ex¬ 
pected to serve as a preventive measure at the beginning of a 
chinch-bug outbreak but that it cannot be depended on as a 
remedy when such an outbreak is fully developed. 
INJURY TO GRASS AS COMPARED WITH AREAS IN WHEAT AND OTHER 
CROPS. 
Meadows and pastures are often invaded by chinch bugs escap¬ 
ing from ripening grain; and where the drouth is so severe as to 
destroy the corn in summer, the second generation may be bred 
to some extent in grass. It also occasionally happens that if 
nothing else offers as food for the hibernating generation, young 
meadows tempt them in spring to settle and lay their eggs and 
there rear their young as in fields of wheat. A study of the rela¬ 
tion of wheat culture to injury to grass will therefore have its special 
*It will be seen (Table T.) that 153 of the 179 towns reporting an injury to corn higher than 
“great" 1 are in Southern Illinois, and only 2H from Central and Northern Illinois (Tables II.'and III.) 
tThis relation of the cron areas in Central Iilinois is doubtless due to the fact that much of the ■ 
wheat of the region is raised in districts not as well adapted to any other crop,—the broken clay 
lands, originally wooded, along the streams. 
