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 larva? 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 by 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 



