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In the North Dakota and South. Dakota areas of most severe infesta- 
tion, wherein- the great flights of July 1938 originated, the number of egg 
pods in the 1937 fall survey averaged from 2 to 6 per square foot, with an 
occasional field averaging from 10 to 15 pods. These numbers of egg pods 
at an average of 20 eggs per pod would theoretically . produce from 300 to 
1,000 nymphs per square yard over large areas and, in some instances, from 
1,500 to 3,000 per square yard. Estimated populations were reported as 
high as 8,000. For every 1 field of egg pods at the above rates, the 
active hoppers hatching from these places could spread over 6 to 60 times 
the area of the original breeding ground at a population of 50 per square 
yard. With many places like those, it is no wonder that the large flights 
developed and similar areas located in the 1938 survey might again produce 
major flights. Although populations of M. mexicanus in Michigan, Wisconsin, 
Iowa, and more eastern States may sometimes equal those in the Western 
Plains area, they do not seem to develop the migratorial habit to the ex- 
tent that plains grasshoppers do. This greatly reduces the hazard from 
this species. 
The Dissostelra longipennis area 
On the Western Plains Dl ssosteira longipenni s moved out to the more 
eastern and southeastern plains area, of Colorado, spread over a wider area 
in the Panhandle of Texas, remained in about the same general area in 
northeastern New Mexico, occurred on the range land, also in the extreme 
northwestern third of the most western county in the Panhandle of Oklahoma, 
and is also an important crop hopper in the rest of the Panhandle area. 
Here the eggs of this species have been found along field margins, in wind- 
blown sand ridges, and in the listed rows of sorghum. When egg pods of 
D. longiipenni s occur in numbers over 1.5 pods per square foot they are 
usually in definite egg beds that are sometimes noticeable and sometimes 
not. These beds run from 1 to 100 acres in size. Some egg deposition 
occurs between the beds but the numbers of pods are usually 1 or less per 
square foot. For the most part the egg beds show severe damage to the 
grass cover, with the grass eaten short by ovipositing females. Spotting 
these egg beds is essential for good, efficient control of this species. 
One ranch of 5,000 acres in Union County, N. Hex., had already marked 36 
beds of 3 to 10 acres in size. It is believed that approximately 6 per- 
cent of the general D. longipenni s area contains some egg pods, with con- 
centration on about a third of this. In the regular egg survey it is im- 
possible to locate nearly all the egg beds and determine their acreage. 
Only the general areas of infestation can be defined and the acreages of 
these determined. For the entire D. longi pennis area this amounted to 
11,217,200 acres in the 1938 survey. 
Species with lesser migratorial tendencies 
Attention is called to the map entitled, "General Distribution of 
Economic Grasshoppers 1938 Survey," where symbols arc used to denote the 
different species. Melanoplus diff orcntiali s is the most abundant in 
southeastern South Dakota, eastern Nebraska., and. western Iowa. In Texa.s 
it is the dominant crop hopper other than D. longipenni s. From the survey 
