46 Trans. Acad. Sci. of St. Louis. 
from early morning, 4 to 6 o’clock, to the evening of the 
same day, the couples usually severing some time between 
5 and 9 o’elock. This length of time seems enormous 
when we consider the brief period they have wherein to 
live and reproduce. We wondered whether this pro- 
longed period was of any increased value to the species; 
whether a longer period of copulation tended to insure 
the fertility of all of the eggs, or whether a large num- 
ber of ova required a longer period of mating to insure 
the fertility of all. 
We also wanted to know just what per cent of the eggs 
were fertile, and if there was a higher percentage of fer- 
tility among the first eggs deposited than among the last. 
This led to the experiments with Cecropia eggs from 
insects which mated from 3 to 48 hours.” In this study 
we found that there is absolutely no relation between 
the time spent in copulation and the fertility of the eggs; 
that those insects which remained in copulo for 3 to 15 
hours deposited eggs showing just as high a per cent of 
fertility as those which continued for 18 to 48 hours. We 
also found that those insects which carried an abnormally 
large number of eggs had just as large a per cent of fer- 
tility as did those with smaller numbers. In the former 
work we found 77% of all the eggs were fertile and 23% 
infertile. 
In 1913 similar work was carried on with 132 females 
of the following 8 lots of Saturniids: 
22 9’s Samia cecropia, River des Péres, St. Louis, normal....... 1913 
14 9’s Samia cecropia, River des Péres, St. L., fluffy cocoons..... 1913 
11 9s Samia cecropin, South “St Louters enc 1913 
16. 9's. Samia cechunia: New York 6rct oo etic 1918 
27 9's Philosatiis cynthia, Philadaiphia . «<<<: 3c. 4. 1913 
20: 9's Pailosamia cynthia: New York. .icisc e 1913 
10 9’s Telea polyphemus, Fall River (29’s) :................... 1913 
Telea polyphemus, St. Louis Bot re ae ee te ee 1912 
Telea polyphemus, New. York. (19°) -< or a ise. 1912 
Telea polyphemus, Augusta, Ga. (69’8) ................. 1913 
2 9’s Samia californica, California 
ms iow) details of this work were published in Biol. Bull, 24: 245- 
