GROWTH AND FEEDING OF HONEYBEE LARVAE. 33 
the part of the nurse bees for its elaboration, it is difficult to explain 
the great amount of time spent by the nurse bees in the cells merely 
on the basis of the belief that food is being fed to the larva all that 
time. That the usual method of feeding is directly to the larval 
mouth is clear from the fact that no significant amount of food is 
ever found in the base or on the sides of the cell of an older larva. 
In the determinations of the weight of food residue in the cell it is 
noteworthy that for each age it is quite uniform. If one dared to 
assume reciprocal feeding, this might perhaps account for the 
peculiar development of the worker bee in the repression of the sex 
organs and other morphological modifications. Wheeler has shown 
that parasites like Orasema, by the withdrawal of food substance 
already assimilated by ant larvae, may bring about morphological 
changes of the same kind as those which distinguish the worker ant 
from the queen. 
The number of inspections and visits to the egg may be accounted 
for, in the light of present knowledge, only by the assumption that 
they are due to the watchfulness of the nurses, since they feed the 
young larvae promptly on hatching. In no other cases except in the 
ants are insects known to care for the eggs. Ants lick the eggs, but 
this is supposed to be for the purpose of sticking them together so 
that* they may be transported in quantity. 
THE LABOR OF THE NURSE BEES. 
Contrary to the common belief, it was noted that bees are not out- 
standing examples of industry. During these observations much 
resting was observed both among the nurse bees and among the other 
workers. Demuth has observed that the average number of trips to 
the field often does not exceed four per day, whereas the time re- 
quired for making such trips and the time required to deposit the 
supplies obtained might readily permit a much larger number. Such 
an apparent lack of industry concerns the present problem only in 
that it is evident that more nurses will be required for a given 
number of larvae in proportion to the time that is taken off from their 
active duties. In the case of nurse bees, however, other considerations 
enter, since considerable time may be required for the elaboration of 
larval food. Thus it is quite possible that a nurse bee, though appar- 
ently idle so far as one can determine, may be active physiologically 
in the production of larval food. Any determination of the efficiency 
of a single nurse bee may be made only bv observations on a large 
number of individual nurse bees extending throughout the day. 
Since the time actually spent in the cell is so great and since the 
time occupied in inspection and in passing from cell to cell is con- 
siderable, in the absence of detailed investigation of the efficiency of 
the individual nurse bee one may only conclude that a single nurse 
bee is able to care for but a few larvae. 
In the case of the bumblebee the queen is able to rear 6 to 16 larvae, 
varying somewhat with the species. The ant queen rears 12 to 15 
larvae, but in this case, as in the case of the bumblebee, the first brood 
is composed of quite small individuals. Those of the bumblebee are 
often not much larger than house flies. All worker honeybees are 
approximately of the same size, and in case supplies are so low that it 
is impossible to feed all the larvae a sufficient amount of food to 
