The Nuptial Flight 127 
night, and between 10:20 and 1:46. The first two came in in 
10 and 12 minutes, and 8 arrived in the first hour. One came in 
at 11:53 the following night. In comparing the returns of the 
mated and unmated individuals, we find that of the 20 unmated 
one, 12 (60 per cent) returned, and of those previously mated, 
9 (50 per cent) came back. This indicates that both are equally 
susceptible. 
Exp. 24. June 20. Wind, southwest; station, 50 feet east. 
By 11 o’clock a number of moths had returned from their test 
flights and were available for another. Since I dared not 
venture far from the house on account of the constant arrival 
of others, I took these, 18 in number, and liberated them in the 
front yard, only 50 feet from the cages, and almost in the 
direction from which the wind came. This happened at 11:07 
Pp. m., just in the time of the greatest activity of these moths. To 
my surprise, 11 returned, all the same night, but strange to say, 
in spite of the fact that they had only thrice the length of the 
room to travel, and they were set free at their most active 
Period, only one made the tiny journey in less than an hour; 
the others required from 114 to 3% hours to come in. Since 
7 did not come back at all (please remember that the females in 
Our cages were the only ones of this species in St. Louis), and 
Since they consumed more time than did those which returned 
from half a mile, the same night, it seems possible that they 
fluttered aimlessly until, in time, they came upon the trail not 
far away. Of course, as an alternative, one may, if one chooses, 
evoke as an explanation for the return of the latter, the theory 
that these moths profited by their recent experiences in coming 
to the roof, and that place memory aided them in making the 
return once more. I offer no argument in favor of either theory. 
Exp. 25. June 22. Wind, southeast; station, 4 mile south. 
The 27 moths used in this test included 10 less than one day old, 
Which had already mated, and 17 from 1 to 114 days old, which 
had not yet mated. These were liberated to one side of the 
direction from which the wind blew, at 9:50 p. m. None of 
these came back the first night, two of the mated moths returned 
the second night and one unmated one the third. Henee we 
must conclude that the ability of the moths to return under 
these conditions is negligible. = 
xp. 26. June 22. Wind, southeast; station, 42 mile east. 
