24 



In the years following this until 1882, the notes, on the corn 

 louse which appeared in periodicals added nothing new to its history, 

 being chiefly repetitions of the matter given in the three articles 

 above referred to. But in the Stark County (Illinois) News in 1882, 

 Dr. E. R. Boardman published an account of the insect in v^^hich 

 we find a few facts additional to those already given. The aerial 

 form is said by this writer to appear on the tassels in the latter 

 part of July and to be also attended by small ants. The lice are 

 said to occur "all the way up the stalk," are badly parasitized by 

 a small ichneumon fly and are preyed upon by the lady bug, 

 Coccinella 9-notata. 



Prof. S. A. Forbes in his report for the year 1882, as Illinois 

 State Entomologist, adds the three lady bugs, Hippodamia maculata, 

 H. convergens, and H. glaciaUs to the list of corn plant louse ene- 

 mies, and the ant which attends the lice is identified by him as 

 Last us Jiuvus. 



The next addition appeared in the third biennial report of the Kan- 

 sas State Board of Agriculture, 1883. In this report Mr. E. A. 

 Popenoe states that he observed in his state, corn plant lice living 

 upon sorghum cane and found the larvae of a syrphus fly preying 

 upon them. 



The latest of the more important contributions appeared in Prof. 

 Forbes' report as State Entomologist for 1883. In this article, 

 broom corn is added to the list of corn louse food-plants and ex- 

 act data as to the occurrence of the two forms during the season 

 are given. Panicum, a common grass of corn fields, is shown to be 

 a possible food-plant. 



These authors have given us the essential facts as far as they 

 are at present known. Besides their work only a few scattered 

 notes and more or less imperfect summaries of the information they 

 give, have appeared in print. As thus recorded the history is im- 

 perfect in several important particulars. (1) It does not tell us 

 where the males and egg-laying females appear and when and where 

 the eggs are laid, and (2) it does not tell us positively what relation 

 the root and aerial forms bear to each other. It was with the pur- 

 pose of deciding these points that the observations recorded in what 

 follows were undertaken. 



A marked irregularity in the growth of corn often noticed in the 

 spring of the year, is frequently found on investigation to be the 

 result of attacks of the root form of the corn louse, and large colo- 

 nies will in such cases be found on the bases of the stems and on 

 the roots of the dwarfed plants. Such plants frequently do not re- 

 cover from the damage done them, but yield at the harvest, if any- 

 thing, small or imperfect ears. The aerial lice also sometimes dwarf 

 the plants where they occur in great numbers, but when the fore 

 part of the season is favorable, the plants gain such a start by 

 the time this form appears that subsequent injuries will not check 

 the growth. 



The damage wrought by these insects occasionally reduces a crop 

 one-half or three-fourths, but damage so severe as this is exceptional 

 and confined to limited areas. The uniform presence of the lice, 

 however, and their wide distribution, taken with the value of the crop 

 they affect, makes them very damaging pests to the people of this 



