LONGEVITY IN SATURNIID MOTHS 199 
careful investigation on the length of pupal, larval and egg stages 
of both sexes, and might lead to a simple and proper explanation 
of this phenomenon. 
COMPARISON OF THE LENGTH OF LIFE OF THE SEXES 
In 1909 it was found that the males of the Cecropia were longer 
lived than the females. In comparing the duration of life of the 
sexes in table 1 we find the males to have lived longer in the 1910 
Cecropias, the New York, and the Incubator Cecropias. In the 
Lunas and the 1911 St. Louis Cecropias there was not a signifi- 
cant difference. In the Polyphemus and Prometheas, the oppo- 
site is true; we find a great difference in favor of the females 
COMPARISON OF THE LENGTH OF LIFE OF MATED AND UNMATED 
INSECTS 
In the entire Cecropia material and also the Prometheas, we 
find no appreciable difference in the length of life of the mated and 
unmated males In the females of the six lots, however, we see 
a significant difference apparently resulting from this condition, 
the unmated females being the longer lived. It is very interesting 
that mating may be such a tax upon the females (it cannot be the 
ovipositing, for the unmated females also experience that) as to 
effect a curtailment of life. No such curtailment due to mating is 
detected in the males. In the Lunas, we find a very slight differ- 
ence in favor of the mated females. This result, however, is derived 
from a small number. Inspection of the two columns of table 1, 
all mated and all unmated insects, shows that the balance swings 
in every case toward longer lives in the unmated insects. 
LAPSE OF TIME BETWEEN LAST EGG LAYING AND DEATH 
According to Weismann’s theory one would expect that in a 
monogamous species the males would die soon after mating, 
while the females would live long enough to completely oviposit. 
In the five lots of Cecropias we find the mean duration of life 
to be even greater in the mated males than in the mated females. 
Surely the continuation of such a long, useless life in the male 
cannot be an adaptation for the good of the species. In both 
