12 Trans. Acad. Sci. of St. Lows. 
contribute something toward determining the duration 
of pupal life. 
In Polyphemus, the two southern localities yielded ma- 
terial of longer life than the two northern ones. May not 
this be considered a natural consequence of the animals 
having favorable conditions of growth and abundant 
supply of food in their developmental stages? Or should 
it be considered an indication that up north the tendency 
is toward going through the life cycle and reproduction 
in a lessened period? 
Comparing now the tabulated summaries of the data 
on these four lots of Polyphemus from as many widely 
remote localities, we find that in absolutely every case 
the mean duration of life in the unmated females exceeds 
that of the males by 1.34 to 2.89 days. We must realize, 
of course, that every hour counts much in the life of one 
of these frail creatures, and that even this brief time 
represents approximately 20% of their normal lifetime. 
We may well disregard the 9 mated individuals in the 
Georgia lot, since their number is inadequate to be reli- 
able for any conclusions. 
It does indeed set one a-searching for reasons and ex- 
planations—to find that this condition of greater life of 
the female should exist in every lot of this material, each 
lot from a region far remote from the other, but this 
condition or character must exist in Polyphemus’ nature, 
and must be a specific part of them as much as any ana- 
tomical character. We feel that these conclusions may 
be considered reliable, since they are based upon the evi- 
dence from so great a number of insects. 
In comparing the mean duration of life of the entire 
population of these five lots, we find some divergence, in 
fact, great divergence when we consider what time 
means to these creatures. The St. Louis 1913 Polyphe- 
mus were the longest lived, with the mean for the whole 
population at 9.59 days. The Augusta material ranked 
next with a mean duration at 9.03 days; the New York 
