40 



MASS. EXPERIMENT STATION BULLETIN 189. 



Average length of life of male moths, 13.1 days; of female moths, 16.86 days. 

 Maximimi length of life of male moths, 29 days; of female moths, 29 days. 

 Minimum length of life of male moths, 6 days; of female moths, 8 days. 



These records were secured in the same manner as has been described 

 in the instance of the first generation adults, and they have the same 

 appUcation and qualification. 



Life Cycle Summary. 



It is rather difficult to give any accurate figures as to the duration of 

 the life cycle of the second generation of the European corn' borer, owing 

 to the varying amount of time spent by the larva in an inactive condition 

 during the late fall, winter and early spring. An attempt will be made, 

 however, to approximate the correct figures by combining the results of 

 the life-history studies as to the duration of the different periods of this 

 generation during the early spring of 1918 and the summer and fall of 

 1918 up to November 30. 



According to these records the average duration of the second gene- 

 ration of the European corn borer was 52.6 days, with a maximum of 

 67 and a minimum of 39 days, as shown by the following table: — 



