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Trixies 1 to 5 show the results of the survey with Hr. Roberts’ 
data summarized in table 1, and tables 2 to 5 giving a summary of all the 
surveyors. In table 2 the average number of egg pods per square foot in 
idle lane 1 is 1.08 and in cropped land adjacent it is 1.13, showing very 
little difference. In range land there is very little difference between 
the average infestations in open and adjacent range lands, but consider- 
able difference between any of the range and the cropped or idle land. 
The infestations in the former were only about one-half to one- third as 
great as in the latter. The figures given in table 3 show that the per- 
centages of adjacent crop-land areas falling into the 1 to 5 classes of 
infestation follow very closely the classification of idle land. Comparing 
such a c 1 as si fi cation of range land in table 4 with the idle land, and 
cultivated crop in table 3, there is considerable difference. For example, 
58 percent of the range can be considered, as "noneconomic," or class 1, as 
it pertains to the migratory species M. mexicanus and its effect on crop 
land in the immediate vicinity. Only 25 percent of the idle land and. 28 
percent of the crop falls in this category. In the class 2, or "light," 
classification there falls 25 percent of the range, 20 percent of the idle 
land, and. 16 percent of the crop land; in the class 3, or "threatening," 
10 percent of the range, 23 percent of the idle land, and. 23 percent of 
the crop; in the class 4, or "severe," 4 percent of the range, 20 percent 
of the idle land, and 19 percent of the crop land. In tho class 5 or 
"very severe," 3 percent of the range, 12 percent of the idle land, and. 
14 percent of the crop laud. This is all based on the number of areas 
and. ficld.s examined. 
From the standpoint of estimating control needs on idle land., it 
could be considered the sane as wheat stubble land, where in the average 
percentage of infestation for a county was applied to the total idle land 
acreage. Where infested, the egg pods of M, mexican us are distributed, 
throughout the field in a similar manner to wheat-stubble infestations 
and there would, be little or no chance of their being plowed under before 
hatching. 
In dealing with range land, there was no criterion for making estimates 
of bait needs; therefore, in table 5 a table of percentages of range areas 
falling into each of the five classes of infestation was set up for each 
State. This was based on the actual numbers of areas examined in each State. 
Applying these percentages to the total), acreages of range land in each State, 
classified the range loud acreage into the five cla.sses of inf cstation. 
From general observations, major migrations, whether by leg or wing, of M. 
mexicanus to crop land, from range land in 1938 occurred in areas where the 
egg pods averaged over 1 pod per square foot, which means above a class 3 
or "threatening" infestation. Therefore, any extra poisoned, bait needed 
for protection from range land could bo estimated by considering the acre- 
ages falling into the class 4 and. class 5 infestations. For the entire 
area this means a total of 6,139,835 acres, which is 6 percent of the 
entire range area.. It is also believed, that only class 5 infestations 
with egg pods numbering above 2 per square foot will produce major flights 
to distant areas. Some 1,977,115 acres come into this classification. 
