October, ’20] FENTON AND HARTZELL: potato leafhopper 
405 
eleven to twelve months. On the other hand the first or summer 
generation in small cages lived from fifteen to sixty days, while in 
large field cages they averaged forty-five to sixty days. Under field 
conditions, probably two months was the average length of life as 
indicated by the fact that there was a definite maximum period of 
hatching of young which extended for approximately forty-five days. 
OviPOSITION 
Owing to the minute size of the egg and its concealment in the plant 
tissues it was impossible to make egg counts. In order to get daily 
records, females were placed with potato leaves for twenty-four hours 
and then these leaves were removed, labeled, and placed with their 
stems in water. From the number of nymphs that issued an estimate 
of the number of fertile eggs was obtained. Difficulty was experienced 
in keeping the potato leaves fresh long enough for the eggs to hatch, 
and so the records are incomplete in this respect. Two series of over¬ 
wintered females were caged to obtain egg records. In June the 
females were caged before they had begun oviposition, while those 
caged July 1 had already been laying since June 6. 
Table I. Average Number of Fertile Eggs Laid per Day by Females 
Number eggs laid per day. 
1 
2 
3 
4 
5 
Number of records. 
72 
21 
5 
4 
2 
The above table summarizes the results. In the majority of cases 
under cage conditions but one egg a day was laid, although frequently 
this was increased to two. Occasionally three, four, or even five were 
deposited and on some days none. Females dissected showed a 
maximum of four eggs matured at one time. 
In general, oviposition of the overwintered females did not begin 
until after the spring flight. A few nymphs were found hatching on 
sweet clover in June for a short time, showing that some females had 
oviposited before migrating to potato. Females dissected directly 
after their appearance on potatoes contained mature eggs, while those 
examined previous to this date did not. Our earliest record for egg 
deposition under cage conditions was June 6, while few were laid after 
July 26. Thus with the overwintered females the oviposition period 
extended from June 6 to July 26, a period of fifty days. 
Attempts were made to secure oviposition on early potatoes by 
females of the first generation in late July. The cages used were large 
glass globes placed over plants that had been cut down and allowed 
to sprout again. These plants were all vigorous and growing at that 
time. Practically no eggs were obtained, showing that these females 
were not ovipositing. 
