= 
a 
> 
1914} Longevity of Insects 329 
Table 4. Proportion Between Temperature and Length of Life. 













Temperature 
brdé- Family _ | High 72° F. Med. 62° F.| | Low 42°F. 
Longevity in Days 
Ave. Diff. Ave. | Diff.| Ave. 
Lo sie Sie ee eee 1.78 af 2.5 It? 4.2 
Muscidae... .: 16 9 | eo 1.5 + 
BEMETOPIGCEA.: |S: 2cec 202.0 2 t= 3% 6.6 ed 6.5 13.5 20 
Latridiide.... 9 9.9 14.5 oot 22.2 
Curculionide.. 3.7 1.3 off 17.6 24.6 
MraAS@@tiaind 6 llr. er ois smcisce EM ees 4.8 1e2 6 4.9 10.9 


The most important conclusion arrived at is that longevity 
is not correlated with systematic groups. Table 3 (Taxonomic 
Groups and Longevity) upon which this conclusion is based 
was compiled in each case from the family in which the greatest 
number of specimens had been included in the experiment. 
It is not probable that the greater variation in a family than in 
the average of the other families of that order as is apparent in 
the table, is due to any greater adaptability to temperature 
changes in that family than in the others. For a comparison 
of the maximum and minimum number of days that the rep- 
resentatives of the different families lived will show that indi- 
vidual variation within the family, in the majority of cases 
where a number of specimens of one species were used in the 
experiment, is as great as individual variation for the group. 
This great individual variation is probably due to the physiologi- 
cal conditions of the individual. For example, in the Capside; 
of the five specimens of one species placed at a high temperature, 
all died in one day except one which moulted and lived for six 
days. Apparently the longevity in this case was due to indi- 
vidual physiological conditions and not to any inherent temper- 
ature adaptability. Such cases could be multiplied. 
We may therefore come to another conclusion, viz: 
4. That longevity at different temperatures is due to 
individual physiological conditions and that any attempt to 
determine the temperature longevity of the species would be 
confused by the variability of the results unless these physiolog- 
ical factors were brought into account. 
