. Bulletin. Natural history; Natural history. 536 Illinois Natukal Histoky Sii'-vkv Bi /pa 5' &£-V£-^£- J3AMACE. Fig. 30. Map of Illinois showing reported area of damage to crops by chinch bugs in 1925, together with inches of rainfall in May (lower figures) and in June (upper figures). elsewhere. An exhaiistive study was made of the data for periods of ahuiidance and scarcity of hugs as iniHcated hy reports of damage to crops in various parts of the state since 1853. Special analysis was given to a very large numher of cases in which a year of severe damage was followed liy a year
. Bulletin. Natural history; Natural history. 536 Illinois Natukal Histoky Sii'-vkv Bi /pa 5' &£-V£-^£- J3AMACE. Fig. 30. Map of Illinois showing reported area of damage to crops by chinch bugs in 1925, together with inches of rainfall in May (lower figures) and in June (upper figures). elsewhere. An exhaiistive study was made of the data for periods of ahuiidance and scarcity of hugs as iniHcated hy reports of damage to crops in various parts of the state since 1853. Special analysis was given to a very large numher of cases in which a year of severe damage was followed liy a year of no damage, and to an almost equally large numl)er of cases in which tlie reverse was true. In each case a hyther- graph was made, according to the jilan tised in the study of the codling moth (Shelford, 1927), by plotting the mean temperature against the mean rainfall for each nmnth nf iJic year. The results are .summarized in Figs. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
