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SOUTH DAKOTA 
Daring the adult surveys in 1934-38, inclusive, collections of 
grasshoppers have "been made in the major environments found in South Dakota.. 
There were 15,105 specimens collected in 1058 in 7 major environments, 
representing 47 different species, Mel ano plus mexi canus was easily the 
dominant grasshopper, constituting 61 percent of the specimens collected 
in small grain and idle land; 37- percent in alfalfa, and 40 ‘percent of thc^ 
total number of specimens collected in the State, II. hivittatus was second 
in numbers for the entire State collection hut was first, at 31 percent, in 
corn. Ageneotettix deorum and Aulocara e lliotti were about equal in numbers, 
at third place. After the 1931 outbreaks of. II. hivittatus and M. dif f erentiali s , 
these two species were greatly reduced in numbers by the drought years which 
followed. Since that time II. mexi canus has boon increasing in relative 
numbers every year, until it reached its peak in 1938. Populations of this 
species from 1,500 to 8,000 per square yard were recorded in crop land, idle 
land, and depleted range land adjacent to crops in the north-central counties. 
These produced major flights in July that swarmed into North Dakota, eastern 
Montana, western South Dakota, and eastern Wyoming* Fall egg surveys in 
1938 indicated that this general movement has reduced the relative numbers 
of M. mexi canus in this and other areas in the eastern half of South Dakota 
and that there is an increase in both M. bivittatus and M. differentials. s 
to equal or supplant M. mexi canus in importance. In the western counties 
M. mexi canus is still the dominant grasshopper, because this area received 
part of the groat flights. There was heavy egg deposition in the Black Hills 
area. The Lyman, Tripp, and Gregory County area show M. dif f erentiali s a.s 
decidedly on the incrca.sc. This was the center of the 1931 outbreak. All 
through the eastern part of the Stele the fall egg surveys showed mixed 
populations of H. mexi canus , M. bivittatus , - and M. dif ferentiali s . 
Hatching began the last week of April and was prolonged throughout 
June. Flights began the last week of June and continued throughout July 
and part of August. These were mostly in a northerly, northwesterly, or 
westerly direction. The almost solid infestation oast of Missouri River 
has been broken up into patchy mixed infestations. 
