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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
time on potato plants for oviposition records. But few nymphs 
hatched in these cages, showing that the overwintered females used 
had largely stopped laying eggs. This was also true in all the early 
potato fields observed, since most of the nymphs noticed on the plants 
were in the late instars and very few were hatching. 
When the hoppers first migrated to the potato fields hundreds were 
examined for the proportion of sexes, which was found to be about 
even. By the middle of June there was a decided preponderance of 
females although there were still many males. June 30 it was very 
difficult to find a male in the field, and after a long search five were 
collected and placed in cages with females. Four of them died within 
a week, and one lived until July 8. 
How Long Do the First Brood Adults Live? 
Females of the first or summer generation were appearing in greatest 
abundance about July 10. Those maturing in cages at that period, 
owing to artificial conditions, began to die within a short time, while 
the longest records were twenty-four to twenty-five days. A month 
later most of this brood had become adult. Some of these later 
matured ones were caged and kept as long as they lived. They began 
to die as in the case of the earlier ones, but the more vigorous lived 
from twenty-five to thirty days and one survived until October 17, 
a period of sixty-one days. 
Males lived on an average of ten days under cage conditions with a 
record of twenty-six days. In the majority of instances it was observed 
that the males died long before the females and shortly after copulation. 
Thus it would seem that the twenty-six day record was unusual. 
How Long Do the Second Brood Adults Live? 
Two series of cages were started in August and September to deter¬ 
mine the length of life of the second generation adults. In the first 
series, one hundred pairs were kept in small cages and examined daily. 
Of this series twenty-two females and five males were alive October 17, 
or approximately 25 per cent. The higher percentage of mortality in 
the males was due to their greater activity. The second series con¬ 
sisted of five large cages each containing one hundred adults that had 
been collected in the field. The majority were alive November 8, 
when last examined, showing that under more natural conditions 
second brood adults lived throughout the fall and were alive at the 
start of winter. 
Thus the second generation adults appeared in the fields in August 
and September and lived throughout the winter, becoming active 
again in the spring, many living until early August, a period of from 
