Experiments in Rhythmetic Periodicity 181 
aS one of differential sensitivity; the change from 54 to 64 
aroused them to a response to the light. The heater was turned 
off; a half-hour later the thermometer still registered 64. The 
light end of the glass box was gently darkened, and the cover 
lifted at the opposite end admitting the light. Within four 
minutes 10 ceeropias and 2 polyphemus (more than half of the 
lot) had traveled to the light side. 
On May 4 the temperature of the room was 59; this was lower 
than that of the three previous days, which had been 71, 66 
and 68. The moths in their cages were very sluggish ; none would 
move about unless prodded. These were 9 in number, 2 male 
and 3 female polyphemus and 4 male ececropias. At 9 p. m. I 
placed an electric heater so that a stream of heat waves would 
pass through all of the cages. Almost immediately they began 
to ‘‘ecome to life,’’ and soon all were fluttering about the tops 
of their cages. There was only one exception; that was a fe- 
male polyphemus only six hours old. When at last the ther- 
mometer among the cages registered 80, she also became active, 
but moved downward. Thus it is apparent that a sudden rise 
in temperature is conducive to the activity of these creatures, 
whereas at a lower temperature they remain motionless. The 
only thing that puzzles me in this matter is the question of just 
how this factor would function in the lives of the wild moths. 
All marked rises in temperature are very sure to occur during 
the day, at which time they are never abroad; hence it seems 
to me there would always be a conflict of reactions, whether 
they should respond to sunlight by sleeping or respond to rising 
temperature by waking. 
Normal Activity. 
I have shown in the electric fan experiments how the occu- 
pants of a cage in close proximity to another cage wherein the 
moths were in a high state of activity were not susceptible to 
suggestion, and remained uninfluenced by the activity of their 
neighbors. In other words, despite the fact that the males could 
See, smell and hear the activity of others near them, they offered 
no imitation. The moths became active only when, in the lan- 
guage of the street, ‘‘they got good and ready.”’ Of course that 
Means when their physiology became attuned to something or 
