10 
Tables of this description were made for each year (1886 and 
1887) and for each crop in each of the areas above mentioned, the 
whole being finally summarized and concluded by a general table 
setting forth the facts for the whole State, and for all the crops 
taken together. 
GENERAL REMARKS UPON THE TABLES. 
Before entering upon a detailed examination of these tables, a 
few critical and explanatory remarks may well be made. 
In the first place, as the data here set forth relate to only one 
of a considerable number of varying conditions which must affect 
the multiplication of the chinch bug and its consequent damage 
to crops, it is not to be expected that any correspondence appar¬ 
ent between wheat culture and chinch-bug injury will be always 
clear and uniform. As it is impossible that conditions of weather, 
general average of soil, methods of cropping and farm manage¬ 
ment, and the like, should be the same for all the groups of 
townships, these and various other influences must have had their 
various effects on the number and condition of the chinch bugs in 
each case, so that a certain amount of variation, upward and down¬ 
ward, will appear in the various series, really due to these con¬ 
cealed but ever present differences of circumstance. 
Where the wheat acreage is very small and the chinch-bug dam¬ 
age light, as in Northern Illinois, these miscellaneous and acci¬ 
dental variations may completely conceal the slight variations to 
be attributed to the insignificant differences in the amount of 
wheat. 
Secondly, although the township assessors are doubtless, on the 
whole, the class of men most likely to judge intelligently and 
accurately concerning the damage done in their townships, this is 
really a difficult matter to estimate, particularly as my questions 
were not put to them until after they had made their annual 
round. The judgment of different men must consequently some¬ 
times have differed widely with respect to like conditions and 
grades of injury. The meaning attached to the terms used in ex¬ 
pressing their estimates of injury must also doubtless have varied 
considerably,—although less, as I judged, than if I had asked men 
not accustomed to think in ratios to give their opinions, in the 
form of percentages of injury. Other variations without significance : 
must have resulted from the fact that in all this investigation the ! 
township has necessarily been taken as an unvarying agricultural 
unit,—of uniform size, and with always the same ratios of culti¬ 
vated and uncultivated lands. 
The more or less serious errors thus arising are all, however, of 
a sort to decrease rapidly with the accumulation of instances, 
being most apparent in the tables of the smaller sections and 
chiefly obliterated in the final tables for the larger sections and 
for the entire State. In the concluding diagram it seems to me 
