156 Trans. Acad. Sct. of St. Louis 
female emanations. This would imply that experience aids and 
augments instinct in this activity—a hypothesis which we men- 
tion but shall not champion at present. Lastly, the moths used 
in this experiment were a random sample of the population, 
that is, all that emerged from a certain lot of cocoons, while the 
males in the preceding experiment had in a way selected them- 
selves from the whole population of wild cecropias in having 
found their way to the roof the first time from the wilds; in 
this preliminary test any of their brothers who were too weak 
or stupid, or did not possess the delicate sensitiveness to respond 
to the call of their mates were of course left behind in the 
woods, so those which responded so obligingly for us in the last 
experiment had really been selected by Nature for this very 
activity, and had proved their ability. This latter condition 
appeals to me as a more plausible explanation for the difference 
in the response of the two groups of males than either of the 
two former factors. This difference in the reaction of the two 
lots of material here shows clearly the danger of drawing sweep- 
ing conclusions from material of unknown history. Here two 
lots of material, outwardly alike, have psychological states, and 
possibly also physiological foundations, quite diverse. 
Exp. 3. This is a continuation of Exp. 2. At 12:15 p. m. 
the females were removed and the box darkened with blankets 
in the usual way. For seven hours the cage was left so, and at 
7:10 p. m. the south end was uncovered. There I saw all of the 
moths in a state of profound quiet, apparently asleep. The 
room was lighted by a 50-watt lamp hanging from the ceiling 
twelve feet away, and in front of the uncovered end of the box. 
When the curtain was lifted a few of them started to flutter 
about, and after ten minutes seven of them had assumed activity 
of some sort. In 25 minutes, this number had not increased. 
This surprised me, because they had now had a long period of 
rest, and instead of midday it was almost night, the time when 
one would expect them to be aroused easily, even without arti- 
ficial stimulus or the presence of females. 
The males, now all quiet, were placed at the dark end of the 
box, and at 7:50 a wire cage containing 8 healthy females was 
placed in the light end. The females remained quiet, . 
motionless, and after three hours only 6 males had worked their 
