32 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
this species may be found on the foliage turnips during October. The 
apterous females feed on roots of this host throughout the winter, some¬ 
times causing an appreciable loss in truck gardens. The alate forms 
are found on the foliage again in March and later are taken on cotton¬ 
wood. On this host, the summer is passed in galls on the leaves. No 
eggs for this species have yet been observed. 
But little attention has yet been given to the economic problems of 
aphids in Texas, consequently there is a great amount of work to be 
done in the future. Although extended studies have been made on 
a few species, the alternate host plants have not been established for a 
single species. Further work along this line should be fruitful of 
results. 
President R. A. Cooley: I will now call for Mr. HartzelPs paper, 
“A Method of Graphically Illustrating the Distribution of Injury by 
an Insect Pest.” 
A METHOD OF GRAPHICALLY ILLUSTRATING THE DIS¬ 
TRIBUTION OF INJURY BY AN INSECT PEST 
By F. Z. Hartzell, Vineyard Laboratory, New York Agricultural Experiment 
Station, Fredonia, N. Y. 
In the study of an insect pest, it frequentfy becomes necessary to 
investigate the feeding habits of the species together with the move¬ 
ment of the pest in cultivated areas. In such a problem, the labor of 
the economic entomologist might be divided into two sections: (1) to 
determine the relations of the insect to the environmental complex; 
(2) to describe and illustrate these relations accurately and concisely. 
Various methods can be used to accomplish this result but the writer 
believes that the simplest and best for the average worker is some form 
of graphical representation. The use of graphic charts and solid mod¬ 
els is common in the study of intricate problems of physics and engi¬ 
neering. If these methods can be adapted to the study of the problems 
of entomology, the workers in this science will have a vast literature 
to assist them. The marked superiority of graphical representation 
over tables or descriptions is sufficient justification for the use of such 
types of charts. 
A common method of illustrating the amount and distribution of 
insect injury is a map of the infested area in which the varying degrees 
of injury are represented by shading. This is not sufficiently accurate 
and does not show the quantitative results we desire. A more accu¬ 
rate method would be to divide the area into small squares and to 
