26 Trans. Acad. Sci. of St. Lowi. 
perature of which varied from 9° to 12° C. Here we 
found that they attained the surprising maximum age of 
32 days, while their contemporaries in ordinary condi- 
tions reached only 13 days. 
Again this year we attempted similar experiments, but 
not in so rigorous a form. The material (two lots of 
Cecropias and one of Polyphemus) was placed in a ce- 
mented basement where the temperature was somewhat 
lower than the out-of-doors, and also considerably lower 
than the room where the other live material was kept. 
The three tables following give the details of the work. 
(See Table 15.) . 
By comparing these 42 insects with their contempo- 
raries, the River des Péres Cecropias, we find the mean 
duration of life considerably greater for those kept in 
the basement, and especially the males of the lot. The 
mean for the entire basement lot is greater than that for 
those kept in the ordinary living-room by 2.66 days. 
From the South St. Louis lot of Cecropias, 38 were 
selected at random and placed in the cool basement. 
(See Table 16.) | 
In this lot the mean for the males and also for the 
whole population is somewhat lower than that for the 
River des Péres basement material—a condition parallel 
with the parent stock. But here too we have a higher 
mean duration of life than for their contemporaries in 
the living-room. We find the cellar conditions prolong- 
ing the life of these 2.84 days over that of their fellows. 
Sixty-six Polyphemus moths, selected at random from 
the Atlanta, Ga., material were subjected to the same 
treatment. (See Table 17.) 
When we compare these with their contemporaries in 
the living-room (Table 6), we are again reminded of ‘‘not 
how long but how well one lives’’; again the laws of com- 
pensation are revealed. These lethargic animals in the 
cellar lived longer than did those in the living-room b 
differences far greater than those recorded for the Pied 
eropias,—viz., the unmated Polyphemus males lived 3.64 
