February, '21] MC colloch: corn leaf aphis 89 



to be infested by the larvae for several seasons, and the insect has been 

 reared to maturity from them. 



Mr. C. H. Turner: In regard to the size of the plant, we had 

 results at the Schenectady laboratory that bore out Dr. Felt's conclu- 

 sions. We had one plot planted the eighth of May and another the last 

 of June. The infestation was almost entirely in the older plot. The 

 moths had crossed the young corn to reach the earlier plot, and they 

 showed selection according to the height of the plant. Most of the eggs 

 were laid on the taller corn, particularly on the large, broad-leaf varie- 

 ties. 



Mr. E. p. Felt: I would like to ask if there are any data to show a 

 tendency toward infestation of one variety or a group of varieties, 

 rather than another. 



Mr. C. H. Turner: Yes. The large, broad-leaf varieties showed 

 evidence of infestation. This was particularly true the first of the 

 season. Later, the smaller varieties, while they did not have as many 

 eggs, in the early part of the season, acquired infestation probably from 

 migration. 



At the end of the season, the stalk infestation was slightly greater 

 in the smaller varieties. The average for the small varieties was about 

 42 per cent. ; in the larger ones, 38 per cent. These figures are approxi- 

 mately correct. 



President Wilmon Newell: The next paper is "The Com Leaf 

 Aphis (Aphis maidis Fitch) in Kansas," by J. W. McColloch. 



THE CORN LEAF APHIS {Aphis maidis Fitch) IN KANSAS^ 



By J. W. McColloch, Associate Entomologist, Kansas Agricultural Experiment 



Station 



The data on which the present paper is based are the results of certain 

 observ^ations made while studying corn insects at this Station. The 

 study was prompted by numerous complaints of injury reported during 

 the past few years, and by an apparent minimizing of the damage done 

 by this insect. The results indicate that in Kansas, A. maidis must be 

 considered not only as a serious pest of corn, but also as an enemy of the 

 various sorghimi crops. It is present every year on these crops, causing 

 more or less injury, but as in the case of many of the aphids, it is difficult 



'Contribution Xo. 62 from the Entomologieal Laboratory, Kansas State Agri- 

 cultural College. This paper embodies some of the results obtained in the prosecu- 

 tion of project 9 of the Agricultural Experiment Station. / 



