10 



BULLETIN" 345, U- S. DEPARTMENT OF AGRICULTURE. 



It is not necessary to point out that there were several other variables 

 among the conditions of these experiments. For example, humidity- 

 is no doubt an important factor, but the lack of complete and accu- 

 rate records of the relative humidity prevents making any statistical 

 analysis of its influence on the length of the preoviposition period. 



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Preoi//pos/f/'onPer/'oc//n e/ay's 



It is interesting to note that Bishopp, Dove, and Parman (1915), in 

 experiments at Dallas, Tex., obtained a 4-day record at an average 

 mean temperature of 87.5° F., while the 4-day records at Arlington, 

 Va., averaged 79.5° F. This and other differences between their 

 results and those recorded in the present paper may in large part be 

 due to the differences in the relative humidity of the two localities. 



