Rau—Longevity in Saturniid Moths. 73 
THE DURATION OF THE PERIOD OF COPULATION OF TROPAEA 
LUNA. 
Notes were made on the time spent in copulo by four 
pairs of 7. luna. One pair remained in copulo 51% 
hours, two pairs for 6% hours, and one pair for 9 hours. 
COCOON SPINNING. 
The following was the only note that could be made 
on the spinning of S. cecropia: 
June 15, at 4 p. m., the cocoon was being commenced; 
Just a few silken threads were spread over the insect. 
At 6 o’elock the next morning the cocoon covered the 
entire insect, but was so thin that the green eaterpillar 
could be seen through it. By 4 p. m. the thickness had 
increased to such an extent that the insect could no 
longer be seen. So with a sharp knife a slice was cut 
off the side of the cocoon, making an opening about 
1% by % inch. Two hours later this was spun over; 
hence, the work was evidently still in progress on the 
inside of the cocoon. 
SUMMARY. 
1. We find that mating does not significantly 
lengthen or shorten the life of the males in any of the 
material observed. 
2. In all of the groups studied the unmated females 
lived longer than the mated females. 
3. In Polyphemus as a whole we find the females 
much longer lived than the males, and for the entire 
population the mean is much greater for the two south- 
ern localities, St. Louis and Augusta, than for the twe 
northern regions, New York and Fall River. 
4. In the Prometheas the mean length of life for 
the whole 1913 Fall River population is much longer 
than in the 1911 Créve Coeur lot. Just the reverse ex- 
ists in the Polyphemus from the two regions. 
