ILLUSTRATIONS. 



Page. 

 Fig. 1. Map showing area in Ohio over which chinch bugs were observed in 



1894 19 



2. Map showing area in Ohio over which chinch bugs occurred in 1895.. . 20 



3. Map showing area in Ohio over which chinch bugs occurred in 1896. . . 21 



4. Map of Ohio giving elevations at various points as determined by rail- 



way surveys 22 



5. Device for preparing oil emulsions 94 



4 



