6 4 
Journal of Agricultural Research 
Vol. XXVI, No. a 
Whether or not this number is greatly in excess of the average egg pro¬ 
duction of the species will be shown by further biological work now under 
way. Several of the other beetles collected in the spring laid more than 
500 eggs during the season but none approached the record of No. 331. 
INCUBATION PERIOD 
The incubation period of the egg (see Table II) varies considerably, 
being influenced chiefly by the prevailing temperatures. During the 
latter part of April and the first week in May, when the temperature 
ranged between 54 0 and 78° F. with a mean of about 68°, the eggs 
almost invariably hatched in 10 days. As the weather became warmer 
the incubation period gradually decreased until during June, July, and 
August, when the temperature ranged between 70° and 90° F. with a 
mean of about 79 0 , only 7 days were required. With the return of 
cooler weather the period again lengthened, and in October, when the 
last eggs of the season were laid, 10 days were again required for incuba¬ 
tion. 
