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small grain and legumes, showed small increases. In very -heavy infesta- 
tions there is a spread into less favorable places, and at such times, the 
population estimates do not indicate material differences in abundance 
"between these and more favorable environments. 
In 1940 and 1941 in western North Edko'ta there was a marked decrease 
in numbers of Melanoplus mexi canus in all habitats, as compared with those 
present in 1938 and 1939.. At the same time there has also been a general 
increase of M. bivittatu s and_M, differential is in the major habitats in that 
area. These species were more abundant in 1941 than in any of the previous 
5 years. Generally speaking this is not true in eastern North Dakota, 
where there has been a general decrease in numbers of If. bivittatus , H. 
mexi canus , and M. different ial is in all habitats. On the other hand, a high 
total population has been maintained by a decided increase in M. f emur- rub rum 
in grassland, legumes, and field margins. The general population for small 
grain was low in 1941* Neither M. bivittatu s nor M. dif f er ent ial i s compares 
with M. n exi canus in importance in North Dakota, and M. femur- rub run even 
less than these first two. in' 1941 M. next earns was at the lowest level 
of the 6 years in all habitats. 
SOUTH DAKOTA 
Although a division should be made between eastern and western South 
Dakota, the western half is mostly range land, and' most --of' the survey data 
came from the eastern half of the State. Small grains, corn, and sorghums 
are the major crops, and idle land and grasslands form a large part of the 
land area.. 
Melanoplu s bivittatus a nd M. dif fer ent ial i s are prominent species 
in South Dakota, and field margins are one of their favorite habitats. Nor 
this reason fence rows, coulee banks, headlands, roadsides, anil roadside 
ditchbanks, in addition to Stubblefields and idle lands, are important- 
sources of infestation. M. m ex i canus is not the predominant species in 
this State, as it is in western North Dakota or Montana, but shares importance 
with M. bivittatus and. M. diff erentialis . Small grain stubble together with 
idle land and poor stands of alfalfa, is the chief source of infestation 
by this species. - Consideration must be given to all three of these species 
and their habitats. M. f emur- rub rum is numerous, especially in eastern 
South Dakota, but is less d.estructive and infestations by it should be 
discounted accordingly. Its chief habitat is alfalfa. Fairly heavy coi>- 
centrations of M. bivittatus and My d. iff erentiali s may be confined mainly 
to native vegetation, and one can easily be misled into believing infest- 
ations by these two species are more serious than they really are. 
From 1936 to 1939, inclusive, Melanoplus m ex i canus was the dominant 
species in practically all environments, reaching extraordinary outbreak 
numbers in 1937 and causing unprecedented flights the next year. During 
1940 and 1941 there has been a decided decline in abundance of this species 
until it now ranks third in numbers. During the same period M. biv it tutus 
and M. different ial is have increased until they rank first and second, 
respectively. 
