Rau—Longevity in Saturmid Moths. 17 
inviting to activity, and in due time expended their quota 
of stored nourishment and died after the normal length 
of life. Further experiments, keeping adult moths in an 
ice-box, proved that cold markedly lengthens their life. 
We have then already stated that the mean duration 
of life of the Cecropia moth was shorter in 1911 than in 
1910; this may be correlated with the fact that the period 
in which they lived was warmer in 1911. A comparison 
of Table 8 with Table 1 (loc. cit., pp. 192 and 183), shows 
that in every case a variation in the length of life accords 
with a simultaneous variation in temperature. 
_ Now we come to the data of the 1918 Cecropia work. 
The St. Louis Cecropias known as the River des Péres 
lot were gathered from the same area, near Forest Park, 
as_in previous years. This time they were sorted into 
two lots, one containing all of the normal cocoons, and 
the other the loosely woven or fluffy cocoons.’ 336 in- 
sects emerged from the normal cocoons between May 9 
and June 16, 220 of which were used for longevity data. 
(See Table 10.) 
Here again the mean duration of life was greater for 
the mated males than the unmated males and vice versa 
for the females. To be sure the mean length of life is 
almost equal for the two classes, ‘‘all mated’’ and ‘‘all 
unmated’’ insects, and also the groups ‘‘all males’’ and 
‘‘all females,’’ but this equality is probably of little sig- 
nificance since it results merely from the counterbalanc- 
ing of the more significant numbers just referred to. The 
mean length of life for this whole population was 9.86 
days. 
Of the 79 insects which emerged from the fluffy cocoons 
between May 5 and June 12, 74 were used for longevity 
notes. (See Table 11.) 
5 These were sorted out and treated separately for the purpose of — 
continuing the study (see Psyche, 18: 168-170, 1911) of this fluffy con- 
dition to ascertain whether it is hereditary, and whether other differ- 
ences, such as longevity, oviposition, etc., make them distinctly differ- 
ent from normal cocooned insects. a0 
