94 Trans. Acad. Sct. of St. Louis 
than the wind brought the message to the males, as Fabre thinks, 
then a fair proportion of them, at least, would have come in with 
the wind at the east windows. 
As the first dim light appeared it was interesting to watch 
from the roof the flight of the approaching moths. They did 
not fly high in the air, on the level with the row of roofs, but 
approached the house fiying near the ground, at the height of 
the shrubbery, and when they came near to the house that 
harbored the females, they would soar upward and bob up over 
the edge of the roof. This showed that if they were following 
the female odor, it did not disseminate in volatile fashion to 
heights above, but was heavier than air and dropped to lower 
levels, at least in this moist atmosphere. In later experiments, 
this low flight was rarely seen; the moths approached from a 
distance flying at about the height of the roof. Probably in 
this case the heavy atmosphere would not permit the female 
odor to disseminate freely, but had a tendency to force it near 
the earth. 
Of the 42 newly captured males, only 3 had frayed wings, 
showing age; 39 had perfect wings with smooth pubescence and 
powdery scales in place, thus proving their youth. In fact, a 
number of them, when handled, ejected the chalky white fluid, 
a trait which is exhibited by these moths only soon after emerg- 
ing. Their wings seem to be thoroughly waterproof, for although 
they came in through the pouring rain, none of them were wet 
or soggy. 
One of these young males, as soon as it flew to the cage, was 
quickly thrust inside, to ascertain how much time would be lost, 
or rather spent, in courtship, before mating began. Within two 
minutes after he had entered the cage, mating had occurred and 
the pair was resting quietly. 
Exp. 13. May 18. Wind, southeast; station, 1 mile north- 
west. The point of liberation was carefully chosen, as nearly as 
I could determine, in the direct path of the wind, but between 
the hour of liberation, 9 p. m., and the hour of their flight, at 
wn, the wind changed and came directly from the south. 
Twenty-four native moths, captured at dawn that morning, were 
used in this test. These moths had been experimented upon in 
the glass box during the day (see p. 152) when the others had 
