96 Trans. Acad. Sci. of St. Louts 
direct path of the wind, but again the wind played tricks on us; 
at 12:30 it changed sharply and blew from the east, and by 3:30 
it was from the north to, the south, or just the opposite from 
what we wished. There was also a thunderstorm. The period 
of their arrival that night was from 3:33 to 4:40 a. m., during 
which time 39 males came to the cages. Five of these had been 
liberated six hours previously ; one had been taken out two days 
before, and the other 33 were all young wild moths. It seemed 
to me that these six experienced fliers found the cages more 
quickly, alighted more quietly and did not spend so much time 
in wild fluttering as did the first time fliers. That would be 
quite natural, since they were older and more experienced. The 
dawn of the following day brought in 9 more marked moths of 
this lot, and even two days after that (May 22 and 23), one 
each. Thus, out of 53 males liberated, 16 eventually returned, 
even amid variously shifting winds. However, the majority of 
them were out for so long a time that their return need not be 
regarded as any more significant than the arrival of any other 
aimless wanderers in the woods and shrubbery. 
Exp. 15. May 20. Wind, imperceptible; no leaf was stir- 
ring; station, 4% mile east. The 39 males, including the 6 which 
had already made two flights to the roof, were now duly marked 
and taken out into the park at 10:30 p.m. During the regular 
period of flight the following dawn,* 93 males came in; of these 
89 were newcomers, one had come to the roof the day before, 
and 3 were members of the lot of 6 that had made two previous 
flights to the roof! That proportion is too large to be passed 
by unnoticed, or to be attributed to mere chance (especially with 
the wind unfavorable) when contrasted with the much larger 
number of other moths which had exactly the same chances but 
less experience. Shall we suspect that these individuals were 
naturally endowed with a higher degree of sensitiveness oF 
ability than their fellows, or that their superior success was the 
result of profiting by experience? Is it possible that these, too, 
would have failed without something akin to place memory ? 
It is possible also that those of subnormal ability were eliminated 
in the first flight, and those taken on the second flight possessed 
superior sensitiveness to stimuli. One out of the remaining 33 
~~ In this case, at dawn the wind was blowing from the south. 
