The Nuptial Flight 113 
two sister species have quite different habits. The cecropias 
concentrate their activity about and just before the hour of 
dawn, and only occasionally some aberrant or strangely stimu- 
lated individuals fare forth during the earlier hours of the 
night. The cynthias, on the other hand, prefer the midnight 
hour for their flight, and seldom are caught abroad at dawn. 
And so this night the first cecropia came in at 3:40 and the last 
at 4:25, 12 native males and 1 blind moth from an earlier test. 
Only a few decrepit old female cecropias remained on the 
roof; it seemed unlikely that these could retain their powers of 
attraction. In fact, on this night and the preceding one, it 
was apparent that the incoming males showed an unusual 
amount of indecision in settling on the cages; they flew about 
aimlessly before they came near the cage, and even then they 
would sometimes fly away without stopping. Out of the 13 
male cecropias, only one eventually settled on a female 
cecropia’s cage, while 6 settled on cages of young cynthias, and 
the remainder were captured with the net when I thought they 
were about to escape. It is interesting to note here that, while 
the cynthias were of various ages from one to six days, one 
cecropia alighted on the cage containing the day-old cynthia 
and 5 cecropias chose the two-day old cynthias and ignored the 
others, 
Exp. 66. June 17. Wind, east;; station, % mile west. The 
Previous experiment gave evidence that the male cecropias are 
to some extent attracted by cynthia females. I now had in my 
Possession two old and decrepit cecropia females. These were 
taken to the rooms below and locked up in an almost air-tight 
closet. Then with plenty of young eynthias on the roof, at 
11:50 p. m. I liberated 30 male cecropias in the path of the 
Wind, as nearly as I could estimate, and % mile distant. The 
lot included 2 males which had returned minus half of each 
antenna, 2 which had returned with blackened eyes, 11 wild 
males had come in at dawn that morning, and 15 from dawn of 
the day before. None of these 30 returned, but 8 young wild 
Cecropias flew in on the roof. 
Exp. 67. June 18. Wind, south; station, 200 feet north. 
Wishing to test again the reaction of cecropia males to eynthia 
females, I took all the males I had, 14 in number, and liberated 
them in the direct breeze. Eleven of these had been fooled once 
