Rau—Longevity in Saturniid Moths. 55 
dissecting the eggs which did not hatch was a far more 
difficult task than in the Cecropia studies. In the latter 
species, the eggs which gave forth nothing showed upon 
dissection one of two alternatives; the egg contained 
either a well-formed embryo, easily distinguished, or a 
yellow mass of dried egg substance. In the Cynthias 
the eggs were very much smaller, and the contents, 
whether the egg mass or the dead embryo, were in most 
cases dark brown, and it required examination under 
magnification to determine whether the masses were in- 
fertile or had partly developed. This scrutiny revealed 
the fact that mortality had occurred at all stages of the 
embryonic development. (See Table 31.) 
Here are 30 females which deposited a total of 6931 
eggs. Of this number 2815 (or 41%) normally hatched, 
and 1584 (23%) were infertile, while the remaining 
36% of the total number deposited failed to develop to 
maturity, or died in embryo. This is the most extreme 
case of waste that we have yet found. Attempts were 
made to sift the data and cull some indication of the 
causes of this, but nothing positive was found. 
The females in this table, 15 in number, which experi- 
enced one mating of unknown duration (probably slightly 
abbreviated), were brought together in a separate table, 
but these showed all degrees of fertility and infertility. 
The 5 moths which mated twice deposited a large num- 
ber of infertile ova, in spite of the additional opportunity 
for their fertilization. The 7 females which went through 
a normal period of mating were likewise assembled. The 
fertility in these is fairly good although the per cent. 
does not run nearly so high as in the other species earlier 
considered. There are only 3 individuals in this table 
in which the artificial interruption of mating was prac- 
ticed. One was in copulo 6 hours, but the next day mated 
again; in this ease almost all of the eggs were fertile. 
In the next, after a 3-hour period of mating 68 eggs, or 
about 20% of the whole number, were infertile, and the 
