23 



ship. Thus, if the injury to small grain in a township was re- 

 ported by its assessor as "considerable" (3), to grass as "none" 

 (0), and to corn as "very great" (5), the total damage would stand 

 at 8. 



Arranging the card reports in the order of these numbers, so 

 obtained, I had a series running from the lowest total injury 

 to the highest, and could bring the different parts of this series 

 into comparison with respect to the average acreage in each crop 

 for 1887* — drawn as before from the abstracts of assessors' reports 

 to the State Department of Agriculture. 



The series of numbers thus obtained is longer and more variable 

 than those presented above, and the tendency of each column is 

 not always easily detected by simple inspection; on which account 

 I have prepared diagrams (pp. 26 to 31), presenting in graphic form 

 the facts contained in the tables, and upon these diagrams the 

 following discussions are based. 



The grades of injury represented by the vertical columns of 

 these diagrams range, as will be seen, from 0 to 20; and the num- 

 bers for average acreage per township at the left of the diagrams 

 run from below upward. A line crossing a diagram from left to 

 right thus indicates increasing grades of injury, while one passing 

 from below upwards indicates an increase in average acreage per 

 township; consequently, if a line, passes obliquely upwards and to 

 the right it shows that increasing injury by chinch bugs went with 

 increased acreage; whereas if it passes obliquely downwards and 

 to the right, it shows a decrease of acreage corresponding to 

 increased injury. 



In the following plates the broken lines have been so drawn 

 as to represent the figures of the tables just mentioned, and lines 

 of average direction have been added to show at a glance the gen- 

 eral significance of the diagrams, and thus to facilitate comparison. 



'Tbese compntalions fur 'all crops were not made foi 1886. 



