66 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 14 



were discontinued in August because by that time practically all the 

 plants were dead from tipbum. 



Summer generation adults did not appear in any numbers until the 

 last week in July when they migrated to the late potato fields where 

 they began depositing eggs. Careful field counts of the number of 

 young hatching were made, but the second brood was insignificant as 

 compared to the first. The development of this generation was no 

 doubt influenced to some extent by the death of the vines during the 

 latter half of August. The remaining adults migrated to curly dock 

 where they remained until frost. N\Tnphs in all stages were found on 

 curly dock as late as October 28, when a freeze occurred in which all of 

 the nymphs and most of the summer generation adults perished. After 

 this host failed them the remaining adults entered into hibernation. 



Longevity 



That the overwintering adults live longer than was supposed is shown 

 by the fact that the females lived an average of 36 days in captivit}-, 

 depositing eggs as late as the last week in August. This would indicate 

 a total length of life of at least twelve months. 



Table I. — Cage Records of Overwintering Fe.males Captured Prior to the Spring Flight 



A comparison of Tables I and II shows that the females introduced 

 after the spring flight lived much longer than those captured early in 

 the season. 



Contrary to the general belief all the females of the summer generation 

 are not killed at the time of frost. One female of this brood lived from 

 August 3 to December G, a period of 124 days, while the average longev- 

 ity of five individuals was approximately 100 days. The results of this 

 year's study indicate that some of the females of the summer generation 

 overwinter. 



