LONGEVITY IN SATURNIID MOTHS 201 
Here we may see many insects, both mated and unmated, 
dying in the very midst of egg-laying. ‘Then again we see others 
which perfectly or almost perfectly oviposited, continuing a useless 
life in some cases up to 38 or even to 96 hours. 
The long life of some females after completely ovipositing, and 
the duration of life of others to insufficient complete egg-laying, 
and the long useless life of the male all lead to the belief that the 
duration of life is not, as Weismann says, an adaptation for the 
good of the species which came about through Natural Selection. 
It seems more natural to assume that the duration of life de- 
pends upon the amount of reserve nutriment which the insects 
acquire at an earlier stage, the activity of the insects, and the 
climatic conditions. The climatic conditions seem to influence 
the insects’ activity; the activity effects the expenditure of reserve 
nutriment, and this expenditure controls the length of life, for 
the nutrition of the imago depends wholly upon this reserve. 
In short, it seems that’the length of life depends to a degree upon 
physiological processes. 
In 1911 data were gathered on the completeness of oviposition 
and the lapse of time between last egg-laying and death in C. 
promethea,?! and the same facts were found to hold for this spe- 
cies as for S. cecropia. In Promethea it was not definitely ascer- 
tained whether or not they are monogamous. | 
THE RELATION OF LONGEVITY TO THE REPRODUCTIVE FUNCTION 
Weismann says: “‘No better arrangement for the maintenance 
of the species . . . . can be imagined than that supplied 
by diminishing the duration of life and simultaneously increasing 
the rapidity of reproduction.” If this were true of the Cecropia 
moth we should find this monogamous species living only long 
enough to carry on the function of reproduction, i.e., males dying 
soon after mating and the females living long enough completely 
to oviposit. This we by no means find. Table 1 shows that the 
males live about as long as the females, even though they are of 
no further use to the species. We have shown that among the 
21 Details are in course of preparation for publication. 
