
- 17 = 
in the heavily infested area of South Dakota, as of the first week in 
November: "Few egg predators were found and eggs were present in large 
numbers and in excellent condition. Six quarts of eggs were obtained for 
laboratory use." 
Prof. H. C. Severin, of the South Dakota Agricultural College, has 
furnished the Bozeman laboratory with over one hundred named species of 
south Dakota grasshoppers, regarding which Doctor Parker says: "This 
is a most valuable addition to our grasshopper collection and will en— 
able us to name by comparison many specimens that would otherwise be 
sent away for determination." 
B. E. Hodgson and H. J. Cronin, of the Arlington, Mass., corn borer 
laboratory, report on the occurrence of partial generations of the corn 
borer in Massachusetts for a series of years: "As early as 1920 it was 
realized that the second generation was not complete; that is, that there 
was a portion of the first-generation borers which failed to make this summer 
pupation. This proportion of single-generation individuals varies from 
year to year, as shown by seasonal—history records. The figures indicate 
that in the vicinity of Arlington, Mass., it was 39 per cent in 1920, none 
fomtgel, 14 per cent in 1922, 40 per cent in 1923, 22 per cent in: 1924, 
40 per cent in 1926, 37 per cent in 1927, 49 per cent in 1928, 27 per cent 
in 1929, 12 per cent in 1930, and 32 per cent in 1931. It was noted several 
years ago that there was a tendency for these single-generation individuals 
to be more numerous on the second early plantings of corn than on the very 
earliest plantings, suggesting that, of the moths emerging from over— 
wintering material, the earliest appearing ones might give rise to two 
generations and the later appearing ones to one generation. Experiments 
were started in 1928 and continued in 1930 and 19351 in an attempt to de- 
termine this point." The summarized results of these experiments indi- 
cate "that there is a decided tendency for early emerging moths to give 
rise to two generations and late emerging moths to one generation. Al- 
though this knowledge is definitely of value in seasonal—history studies, 
it may serve a practical purpose in helping to solve other problems in 
studies of abundance, parasites, and other control methods." 
C. H. Batchelder, of the Arlington, Mass., corn borer laboratory, 
has completed his experiments in the sterilization of sweet corn by means 
of low temperatures to a point where he is able to furnish the following 
report: "Experiments reported here in November indicated that, due to the 
resistance to cold, characteristic of the European corn borer, and because 
it inhabits a host providing very effective insulation, green sweet corn 
must be processed by means of zero or subzero temperatures (Fahrenheit). 
The several methods of refrigeration meeting these requirements and avail- 
able for the practice of cold sterilization are usually referred to as 
‘slow freeze,' ‘sharp process,' and 'quick-freeze' processing. Infested 
sweet corn ears were refrigerated by these methods during September, 1931. 
It was found that when green "Whipples Yellow," one of the largest of the 
sweet corn varieties, is exposed between the shelving of a -—22° F. 
