120 Trans. Acad. Sci. of St. Louis 
Too many factors are complicated in these data to throw much 
light on the distance traveled and the per cent that returned. 
It would be interesting indeed if all the interfering factors 
could be eliminated, such as distraction of wild moths, shifting 
winds, ete., and a pure test could be made of the distance from 
which they are capable of detecting and discovering their mates. 
Surely everyone will agree that the return of 16 marked moths, 
or more than 10 per cent of those liberated in this test, from a 
distance of three miles is truly marvellous. Since this was ac- 
complished amid the aforementioned conflicting factors, it is 
logical to believe that their ability per se to pick up and follow 
a trail would far exceed this surprising distance. 
The table reveals the fact also that the experienced males, i. e., 
those which have made one or more successful flights to the 
roof, came back in a larger per cent of cases than did those out 
for their first flight. In 178 cases of the males taken out for 
the first time, 32, or 18 per cent, returned; in 557 records of 
males taken out that had previously flown to the roof one or 
more times, we got a return of 138, or nearly 25 per cent. This 
compares well with the results from cynthias, described else- 
where in these pages, in which we get returns for inexperienced 
and experienced fliers of 3014 and 37 respectively. In both 
species the difference between the two classes is 7 per cent. 
The hour of activity of the cecropias was always (excepting 
a few cases during bright moonlight or abnormal temperature) 
between 3:30 and 4:30 a.m. Even when the moths were liber- 
ated no further distant than our own back yard, and either 
early in the night or at 2:30 a. m., they showed no inclination to 
come in until 3:30, probably when the light stimulus began its 
work. At first thought the reader might suspect that the hour 
of dawn would vary considerably during the long period of 
experimentation, but while this would be true for any other time 
earlier or later in the summer, the hour of dawn just before 
and after the summer solstice is more nearly constant than at 
any other time during the summer. 
In summarizing the work on cecropias, we must not overlook 
the evidence gleaned from the behavior of moths deprived of 
the use of their eyes and antennae. We find blind males fiying 
to the females quite as readily as those with eyes uncovered. 
