152 Trans. Acad. Sct. of St. Louis 
purely rhythmic if the response can be attributed to sensory 
reaction. The following experiments will help clear up this 
point. 
Experiments to Test Perception of Odor. (Cecropia). 
The results of the long-distance experiments justified the 
assumption that the odor of the females is carried by the wind 
and is perceived by the male some distance away. The follow- 
ing close-up experiments were made to test this theory. 
Exp. 1. May 18. At dawn many male cecropias came to 
the roof. Thirty-nine of these were placed in the glass box.* 
The temperature was 68° F. In an hour they were all quietly 
settled; then I gently placed two females (each in a small wire 
eage), aged 4 and 8 days, in the box. This change elicited 
absolutely no movement on the part of any of the individuals 
of either sex; all rested so quietly that they appeared in pro- 
found sleep. The females were not expected to be aggressive, 
and the males may have been fatigued after their long morning 
flight over the roof-tops to reach the cages. At 7:17, after a 
lapse of 17 minutes, the young female began slowly to move 
about, then suddenly vibrated her wings in a very excited man- 
ner. Within a very few minutes, two males nearest her cage too 
became thoroughly excited. As she continued rhythmically 
vibrating her wings, another small group in the opposite dark 
corner began to show activity. (The glass box was at this time 
covered with a heavy blanket, which was lifted from one end, 
thus admitting the dim light of a cloudy day. The males were 
all near the dark end of the box, and the females in the center.) 
As the fluttering of the few males at the dark end continued, I 
thought they would settle on the cages of the females in the 
center of the box, but therein I was mistaken; all those which 
were aroused to activity fluttered past the females and on into 
the light portion of the box, and there fluttered violently up 
and down, bumping their heads against the glass. When the 
females rested a few minutes later, I counted eleven males 
ing against the glass at the light. The males, ar : 
from quiescence at the dark end of the box by the agitation © 
a thirty- 
glass 
*This glass box used throughout these experiments was 
two-gallon yreetnenh with glass sides and iron bottom; either 4 
or an opaque cover could be improvised as desired. 
