200 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
termine the amount of materials which the grower will need to poison 
the grasshoppers. 
Attempts have been made to estimate the number of grasshoppers by 
collectors who used nets of the same size and made a certain number of 
sweepings in a given number of steps but we have discarded this method 
because it was felt that a compilation of the reports of several workers 
using this method was not accurate enough for scientific purposes. 
Sweepings made at different times of the day, under varying climatic 
conditions, in different crops, together with the varying speed of the 
operators upset the uniformity of such reports. 
While not essential it is highly desirous that sufficient plots of crop 
be used in carrying out a control experiment that have equal or nearly 
equal degrees of infestation. When the grasshoppers are adult the 
person about to engage in such an experiment may approach his plots 
in the early morning as soon as it is light enough to see distinctly and 
before the grasshoppers move readily. By observing caution the grass¬ 
hoppers that are resting inside of a given unit, say a square yard, can be 
counted. Naturally, counts in such plots must be made in several 
places. The locations where counts are made may be chosen in much 
the same manner as that adopted by an adjuster in determining the 
amount of hail damage to a crop. When the grasshoppers are still 
quite small, such a method does not give as accurate a count as when 
larger. Young grasshoppers are inclined to shelter themselves under 
close-growing foliage and in cracks and rubbish during the nights and 
colder parts of the first daylight hours. Under such conditions the 
number of grasshoppers in a predetermined unit can be counted with the 
aid of a low-powered field glass, by slowly approaching near the places 
chosen at random and remaining there quiet long enough to permit the 
few grasshoppers that have fled to be replaced. It is easier to do this 
during the extreme heat of the day when they are sluggish. At this 
time the grasshoppers are resting in the foliage, on the tops of clods of 
earth and in spots bare of vegetation. This method may also be used 
with adults. • 
While the damage that grasshoppers do to individual plants is plainly 
'discernible, the amount of damage to a crop is not always readily esti¬ 
mated. It sometimes happens that in the spring of the year small grain 
is ravaged by young grasshoppers coming in from adjacent egg beds. 
They eat as fast as they travel leaving borders of bare soil. If these are 
killed before more damage is done, the percentage of damage can 
readily be calculated. It is not often that a second growth comes from 
