FEEDING HABITS OF THE JAPANESE BEETLE. 11 
As the heat increases during the day the beetles become more 
active and disperse to taller plants until the early afternoon period, 
when they may be abundant on the tallest elms, oaks, and maples. 
After 3 o'clock their flight is toward the ground and to lower-growing 
plants. 
One sex is as likely as the other to begin a new infestation, pro- 
viding there are equal numbers of both sexes flying at the time. 
Hourly and half-hourly collections of adults from several food 
plants showed the proportion of females to males was highest between 
12 noon and 2 p. m. and lowest between 7 p. m. and 7 a. m. The 
taller plants, such as apple, showed the most marked differences in 
the proportion of the sexes at different times, while low-growing 
species, such as smartweed, showed the least. This indicates that 
many females leaving the taller trees may not enter the soil, but 
remain on low weeds during the night. 
The average length of the feeding period of the beetles on apple 
foliage between the hours of 7.30 and 10 a. m., as observed in this 
study, was 21.65 minutes for the males and 40.24 minutes for the 
females. During the period 11 a. m. to 2 p. m., the males fed on 
an average 23.3 minutes and the females 46 minutes. The average 
length of the feeding period was noted during the afternoon on 
grapes. In this case it was found that the males fed on an average 
21.54 minutes, while the females fed for 40.18 minutes. On rainy 
days the beetles are more or less inactive and less feeding occurs 
than on warm, clear days. 
Data were collected relative to the rate at which the beetles feed. 
It was found that on apple the males fed at the rate of 40.18 square 
millimeters an hour, whereas the females consumed foliage at the 
rate of 43.519 square millimeters an hour. 
