8 



fiom townships in Central and Northern Illinois in -which not an 

 acre of wheat was reported, to others — mostly in the southern 

 part of the State — where the wheat area ranged from 10,000 to 

 13,000 acres per township.* 



Further, where damage had been done, it was in some cases 

 barely perceptible for the first time in many years, and in others had 

 been repeated with extreme severity for several successive seasons. 

 This made easily possible elaborate comparison in all parts of the 

 State between the wheat acreage and the amount of chinch-bug 

 damage done to the principal crops. If the latter was found to 

 vary generally with the former, the area in wheat increasing or 

 diminishing where injury to corn, grass, etc., was greater or less, 

 the presumption would be very strong that there was some con- 

 nection of cause and effect between these two sets of data. I con- 

 sequently undertook to collect, classify, and discuss the facts 

 obtainable in this State bearing on this important matter, — a labor 

 which has absorbed much of my own time and the greater part 

 of that of two assistants during some months of the summer and 

 fall. The scope of my inquiry was finally widened so as to in- 

 clude an examination of the relations of chinch-bug injury to corn 

 and grass, as well as to wheat and the other small grains, with a 

 view to showing the kind of rotation or cropping prevalent in the 

 worst infested districts as compared with those nearly or quite 

 free from damage. 



COLLECTION OF DATA. 



For the facts of both orders, I had recourse to township as- 

 sessors throughout the State. Those concerning acreage in wheat 

 and other crops were compiled from the Assessors' Keports for 

 the years 1886 and 1887 on file at the Stat.^ Capitol; and those 

 concerning insect injury to small grain, corn, and grass, were 

 secured by correspondence with the officers who made the assess- 

 ment for 1887. In order that the last mentioned facts might be 

 uniformly stated in a way to make them available for tabulation, 

 the following slip and postal-card circular were sent to every as- 

 sessor in the State. The terms selected for the card of inquiry 

 made a series as uniformly graded as was convenient, of expres- 

 sions to which every one was accustomed and to which all would 

 attach a practically identical meaning. 



Office State Entomologist, 

 CuAMPAioN, III., March 5. 1H88. 



Deau Siu: Ah an important item in an invostlffation of the relations of wheat culture to 

 the chinch buK, which I have undortaken, 1 need an estimate, byassossorH. of the amount of chinch- 

 bag injury in their respective towns for the season of 18H7. Will you be kind onoUKh to not« upon 

 the card enclosed yourJudRnient of this mntter, returning to me without tinnoccHsary delay? 



Very llospectftilly, 



S. A. FORBES, 

 S/<if, KiitoDiolo list. 



•This lust In WaHhlngtDU county. 



