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ground which had previously been in corn, and that its injuries could 

 consequently be arrested by judicious rotation, seems doubtful in the 

 light of our recent experience. 



Early in July, this season, reports reached me from the country 

 surrounding Champaign, of a severe and mysterious injury to corn. 

 This condition of alfairs was discovered in eight adjacent lields, the 

 areas affected varying from one third to four fifths of the separate 

 lields. The injury, from all the attendant circumstances, seemed to 

 me to be almost certainly due to plant lice. No great numbers were 

 in the ground at the time, but concurrent testimony to their abun- 

 dance on the roots a few days previously, was too weighty to be 

 ignored, two intelligent farmers reporting that the plant lice had 

 emerged from the ground in very large numbers, and scattered just 

 before my visit to the fields. 



The notorious soft maple bark louse {Piilvinarin innumerahUis) , 

 which so seriously injured soft maple trees last year, seemed to the 

 casual observer, in spring, to threaten an equal injury this season ; but 

 upon close inspection late in June, the cottony egg masses of the 

 female were found, in nearly every instance examined, to harbor a 

 coccinellid larvae (Hyperaspis), by which the eggs were being rapidly 

 devoured ; and before the end of the season the pest was reduced to 

 insignificance throughout the greater part of the area infested by it. 

 In here and there a locality where it had been less abundant than 

 usual last year, it reached its climax this, but the total damage 

 done was slight. 



The winter wheat near Champaign was last year very badly dam- 

 aged by spring frosts, but late in April I learned of injury to a few 

 fields, of such a character that the owners could not attribute it to 

 the weather. In these fields great numbers of a small earth-worm 

 (Lumbriculus) were found collected about the roots of the dead 

 plants, occurring also to some extent among the living wheat, but 

 far less abundantly. To the presence of these worms some of the 

 farmers attributed the damage done, and the question consequently 

 arose whether these worms might not rather have been attracted 

 to the wheat after the death of the plants, finding in the dead and 

 half-decayed vegetation an abundance of food. To determine this 

 matter we planted two small boxes of wheat, stocking one of them 

 with 160 worms and leaving the other free. The wheat grew freely 

 in both boxes and Avas entirely uninjured by the worms during sev- 

 eral weeks, when the experiment was discontinued. 



