304 
Mr, Skoog, in the northern '^ea, ' :pr$i)ared a table showing the dif- 
ferences between the average number of egg pods per sq.uare foot in the 
spring and fall egg surveys of 1939 in his area. 
Table 5.— Comparison between agg pods -per square foot, 
spring and fall surve.Vs^ 1939 
Area 
Average number nods, -ber sQuare foot 
Surinfi 1939 
Pall 1939 
Eastern Montana - - - - - - - - 
2,60 
■ 0.16 
Western North Dakota - - - - - 
■ . - 6,45 ■ 
,36 
Both of these tables indicate a great reduction in the infestations 
in the main M. meyicanufl area. 
Second Generation of Melanoplus mesleaims 
Early in Au^st 1939 a second generation of mericanus began 
hatching in western Kansas^ the Oklahoma Panhandle, the northern part of 
the Texas Panhandle, and in sou.theastem Colorado, In this region, the 
first generation was of minor importance in Texas but increased in numbers 
northward until it comprised half the grasshopper population in parts of 
Kansas and Oklahoma. In the Oklahoma Panhandle the first generation was 
reduced by baiting operations to an average of less than 5 per square yard 
in marginal areas and 1 per square yard in fields. The light residual 
population laid. many eggs,- of which at least 95 percent hatched. The 
second generation r^^lted in a surprising 'increase in population, and 
proved more iii^ortaht than the first generation, with respect to crop damage. 
Prom a normal- to- light spring infestation there developed a light-to- 
threatening second generation, and from eggs of the second generation a 
threatening-to-severe infestation developed in the spring of 1940, 
Melnno-nlug bjyittatus and Melanoulus differentialis Area 
This area included, southeastern and- south- central South Dakota, 
extreme southwestern Minnesota, western Iowa, northwestern Missouri, and 
eastern Nebraska, Very few observations were made in Missouri because of 
the low grasshopper populations found there. The survey supervisor for 
this area was D, Rj,-- Lindsay, ^hd the following discussion is based on his 
notes and observations, ! 
1 
There were three major - species involved in this area — Malanoolus 
bivittatus . M. differentialis i and M. ’ m'eAcanus . named in the order of 
their im-portance- ■■ - Melanoplus femur-rubrum was also abundant in places. 
Both M. differentialis and M. femur- rubrum hatch 2 or 3 weeks later than 
the other two, and this in itself prolonged the hatching period in this 
area, which began the first week of May and continued to August. 
