Rau—Longevity in Saturniid Moths. 69 
PROBABLE TWO-BROODEDNESS OF T. POLYPHEMUS. 
All of our Polyphemus adults—and a great number 
we had from several localities—emerged in May or June 
and one group emerged in good numbers as early as the 
last of April. Therefore we were much surprised to take 
a female on August 11, 1912, which was in good condition. 
The fact that she laid fertile eggs proves that there must 
also have been males lurking somewhere this late in the 
season. With what we know of the longevity of this spe- 
cies, it is impossible to believe this to be one which had 
emerged in the spring. This species may possibly be 
double-brooded. 
On July 30, 1913, a male Polyphemus was brought to 
me, apparently in good condition. 
INFERTILITY OF POLYPHEMUS EGGS. 
Since the Polyphemus were seldom seen in copulo, it 
was thought that possibly mating might occur for such 
brief periods that it was only by chance that they 
could be seen. To test this point, all of the eggs of 25 
females of this species which had had ample opportunity 
for mating were cared for until long past hatching time 
to see whether, perchance, fertilization had occurred un- 
noticed. But they all soon shrivelled, and none at all 
ever hatched. This strongly indicates that mating does 
not oceur for brief intervals on the sly, and also that 
these females do not lay parthenogenetic eggs. 
CROSSINGS. 
On June 3 a female Polyphemus mated with a male 
Cecropia from 6a.m.to6p.m. The female died the next 
day without ovipositing. 
On May 9 a 10-day-old female Polyphemus mated with 
a male Cecropia. It lived for a few days afterward, and 
deposited 4 eggs, which proved infertile. 
After we found it impossible to get the Prometheas to 
