Experiments in Rhythmetic Periodicity 159 
to this stimulus, either by flying about, fluttering or waving the 
wings. 
To again see if they would act in the same manner in a 
breeze of clear air of the same strength, I gently removed the 
cage of females from the path of the breeze. There was no 
period of rest given the males between these two trials, but 
when they were in their greatest activity the cage of females 
was gently slipped away. It was interesting indeed to see that 
in just three minutes, eight of them became quiet, and in two 
minutes more the other two subsided. And so they continued 
motionless, even when the breeze gently pushed a wing this 
way or that. After a quarter of an hour, the cage of females 
was again pushed between them and the fan, and within five 
minutes three males were in a state of excitement. The fact 
that the response was not so general this time may have been 
due to one of three things: the males may have been fatigued ; 
they may have become accustomed to this stimulus to which 
they could not normally respond while imprisoned; or the wind 
from the fan may have had a cooling effect on the pores or 
organs of odor of the females and reduced their efficiency. 
This experiment substantiates the results from the glass box 
experiments, and the theory that the males come great distances 
to reach the females by following the odor on the wind. This 
test indicates also that not all males react in the same way, but 
while this seems to be so, we must be cautious about saying it 
with too much positiveness because with our crudely improvised 
technique it seems quife possible that the odor-laden air was 
not equally distributed over the entire cage. These reactions, 
please remember, were not made at the hour of their natural 
time of activity, which is early dawn, but at high noon, which 
is their midnight. These males were wild native ones which 
had come to the females on my roof; it would be interesting to 
see what responses we would get from males which had emerged 
from their cocoons in the laboratory, in other words, a strictly 
random sample, unmodified by experience or selection. 
Exp. 6. May 30. 6:25 p. m. This experiment was made 
upon 18 males which had come in at dawn of the day before. 
The fan was placed three feet away, and a stream of pure alr 
was thrown upon them. After ten minutes of this treatment, 
