It is possible, also, that Ihe normal projiress of agriculture may make 

 virtually universal tanniiii; practices which will serve as permanent 

 preventives of injury by certain insects which have previously done great 

 harm. If, for example, it should beccnne the general rule to raise corn 

 on the same ground for only two or three years at a time, injuries by the 

 corn root-worm would apparently be reduced to insignilicance. No such 

 event has anywhere occurred in this country, however, and the rule of 

 economic entomology has thus far been "once an enemy ah\ays an 

 enemy," the list of insect pests increasing from time to time, but never 

 diminishing. 



Discussion of Species. 



In the remainder of this report I give all pertinent facts of any impor- 

 tance known to me concerning the corn insects which frequent that part 

 of the plant which grows above the surface of the ground, exclusive, 

 however, of those which infest the grain or the fodder after these have 

 been removed from the field. In cu'der to make this treatise virtually 

 complete for the corn insects as a group, I have made references on page 

 69 to a previous article on injuries to the seeds and root« of Indian 

 corn, published in my Seventh Report as State Entomologist — the 

 l^lighteenth of the office series — and also, in briefer form, in Bulletin 

 44 of the State Agrit-ultural l']xperiment Station. The abo\'e-mentioned 

 Eighteenth Report may be found in volume 31 of the Transactions of 

 the Illinois State Department of Agrii'ulture, whore it is printed as an 

 appendix. 



ECONOMIC GROUP 1. 



(.Tlio inoro iiuport;int insects: those seriously injurious to the crop, either as loeallv 

 and oeeasionally th'stnietive or as widely and frenuentlv harnilul.) 



Insects Injurious to the Plant above Ground. 

 Synopsis of Injuries. 



The plant cut off when }'oung at or near the surface of the ground by 

 a whitish, grayish, or blackish caterpillar frequently found in 



the earth near the injured plant 



Cutworms {Agroiis, Hadcua, etc.). 17 



The stalk of the young plant eaten into or irregularly gnawed off. 

 The leaves also irregularly eaten. A small, spotted, reddish 

 caterpillar found muler ground near the base of the plant in a 



small mass of earth held together by a web 



Sod Web-worms or Hoot Web-worms (Cramlms). 30 



