The Life of the Individual 
129 
attempts to do by keeping the bees in the cellar or by pack¬ 
ing the hives during the coldest months. As will be explained 
in the chapter on wintering, the character of the food is 
an important factor in the reduction of the necessary labor. 
Possible determining factors. 
The cause of the wearing out of bees is not fully under¬ 
stood, because there are so many phases of bee physiology 
about which we are ignorant. An old bee loses the hairs 
on the body and the wings often become frayed. These 
parts are not replaced, since in the adult they are non-living 
chitinous structures, but it can scarcely be believed that 
these factors are sufficient to cause the death of the insect. 
The fact that the larger number of bees die outside the hive 
during the active season perhaps lends weight to a belief 
that worn-out wings have failed to carry them back. How¬ 
ever, if bees are confined in a cage and are constantly stimu¬ 
lated, they wear themselves out and die, when wings could 
be of no help to them. Koschevnikov 1 has described the 
fat body of the bee and records that in old age the fat cells 
become less vacuolated and the cells are filled with a granu¬ 
lar plasma, while the cells become united into a syncytium, 
in which the cell boundaries are lost and the nuclei remain 
distinct. The cenocytes are rather mysterious cells, found 
in the fat bodies of insects. In the old bee, these become 
filled with yellow granules, which Koschevnikov thinks are 
excretory products which cannot be eliminated but are 
simply retained by the cells. These facts suggest the possi¬ 
bility that old age in a bee is due to lack of the excretory 
function of these cells, but far more evidence is necessary 
for adequate explanation. 
Some comparisons with other insects help to make clear 
the difficulty of the problem which confronts us in the 
phenomenon of old age in the bee. 2 Worker ants have been 
1 Koschevnikov, G. A., 1900. Uebcrden Fettkorper und die (Enocyten 
dor Honigbiene (Apis mclUfera, L.) Zool. Anz., XXIII, pp. 337—353. 
2 For an interesting discussion of the duration of life, the reader is re- 
