1914] ~ Longevity of Insects : | 349 
at a low ebb—second; there is apparently a physiologically iso- 
lation of parts—this isolation is evident'in the following ways: 
the larvze often become entangled or bound by a thread of a 
spinning larva close by. The bonds which are thus tied 
about them become so tight that the insect is almost cut in two. 
I have often observed that the posterior half of the insect may 
have died from the effect of this isolation and decay set in while 
the anterior part may remain-unaffected for many days. Dis- 
ease also has been observed.in these experiments to spread 
very slowly through the, insect—this also can be accepted as 
evidence of the overfed and senescent condition of the larva 
which is about to hibernate.. This has generally been found to 
be the case in hibernating mammals on exposure to disease. 
(Carlier and Dubois (17). 
It seems probable then, that the. overfed condition of the 
insect and the ‘‘old”’ state of the cell has reduced the permeabil- 
ity to a great degree and as a result, the rate of metabolic pro- 
cesses is greatly lowered. The loss of water probably results 
in the alveolar walls going out of solution and being cast out. 
In starving Planarians and in those which have undergone 
regeneration according to Nussbaum and Oxner (40), granules 
are present throughout the tissues. These granules are absorbed 
‘by phagocytes from the body wall—a similar process takes place 
in the potato beetle during hibernation, according to Tower 
‘and is characteristic of the process of histolysis, according to 
Henneguy (22). 
During the molt, pupal period, and apparently in hibernating 
Codling moth larve (as I have observed in my experiments) 
these granules are very abundant. 
From these considerations, it is possible to formulate certain 
working hypotheses which will serve as guides for further 
experimentation and consideration of which may throw further 
light on the nature of the processes of hibernation. These 
hypotheses are: 
1. That temperature is but a single factor and not neces- 
sarily the controlling one in hibernation. 
2. That hibernation is usually concomitant with overfeed- 
ing and may be a result of that condition or the result 
of accumulation of inactive substances in the cyto- 
plasm of the cell due to feeding on innutritive food. 
