STUDIES ON PERILLUS BIOCULATUS FAB. 61 
at Batavia, N. Y., while the 1921 lot was reared at St. Paul, Minn. 
The data are arranged in a table similar to that given by Drake (1920) 
for Nezara viridula Linnaeus. 
Owing to higher average temperatures prevailing during July and 
August, the average time from egg to adult in New York was found 
to be 24 or 25 days. This time was duplicated by other lots reared, 
but for which the exact time for individual instars was not always 
kept. During September the period of development for nymphs is 
more extended, some not completing their transformations before the 
potato beetles enter the ground. From eggs which hatched Septem- 
ber 2, 1913, and were reared in the laboratory, two individuals attained 
the fifth instar during October. These were kept for hibernation 
but both were found dead on November 1. 
In Minnesota, where eggs were laid on June 15, 1921, adults did 
not emerge until July 20, a period of 35 days. ‘In this lot it is possible 
that growth was somewhat retarded because of irregular feeding, 
still it is doubtful if the bugs would have found more food in the 
potato patch during their eaily stages. From eggs deposited July 17, 
1921, adults emerged August 15, a period of 28 days. Another lot 
of eggs deposited July 18 developed adults on August 16, taking the 
same number of days for development. From ihis it may be seen 
that during the most favorable growing period of 1921 three or four 
days more were required to mature adults at St. Paul than was the 
case at Batavia, N. Y., in 1913 and 1914. 
The minimum time observed for an individual bug to pass from 
egg to adult stage was found to be 21 days, in 1914, at Batavia, N. A's 
