BUCKINGHAM. — DIVISION OF LABOR AMONG ANTS. 479 



cent) actively or passively engaged, and in one of the three colonies 

 (87) there was no such activity during my observations. In each of 

 the other two colonies the percentage engaged in this process was 

 about equal, but as there was considerable difference in the whole 

 number (89 and 173) of ants in these colonies, it follows that the 

 number engaged is not closely correlated with the number of ants in 

 the colony. 



In this species I saw no soldiers either regurgitating or receiving re- 

 gurgitated food. In one nest, as before stated, this activity was not 

 seen at all ; in the others, minors fed minors, 0.01 per cent giving and 

 0.01 per cent receiving food in each colony. In this species, then, so 

 far as my observations go, regurgitating is limited to the minors. 



4. Licking and Being Licked. 



1. Methods. — These two sets of activities, being also reciprocal, 

 were observed at the same time. In one chamber was a wet sponge 

 covered with cheese cloth ; in the other, food. Observations were 

 made once every two minutes, and the number of ants of each class, 

 both those licking other ants, and those being licked, was recorded 

 separately. 



2. Observations. — One hundred observations were made on each of 

 three colonies. Here, too, only a few ants licked or were licked (0.2 

 percent, 0.7 per cent, 0.5 per cent; and 0.2 per cent, 0.6 percent, 0.5 

 per cent), and the per cents of ants so engaged in the different colonies 

 of the species do not agree closely. In this species of Pheidole the 

 proportion of ants engaged seems to be independent of the. total num- 

 ber of ants in the colony. 



In all cases in this species the minors were more active than the 

 soldiers, as the latter did not lick other ants at all. In the matter of 

 being licked, two colonies gave more minors (0.2 per cent > per cent ; 

 0.6 per cent > 0.4 per cent), and one, more soldiers (0.5 per cent < 1 

 per cent). 



5. Tending the Young. 



1. Methods. — In this experiment it was not practicable to have 

 earth on the floor of the nest, as the ants were inclined to make use of 

 the earth in which to hide their young ; therefore a wet sponge covered 

 with cheese cloth was put into one of the chambers, while the food was 

 placed in the other. At intervals of one minute a count was made of 

 the number of ants of each class holding young in their mouths, or 

 otherwise seeming to care for them. As an individual in possession of 

 young frequently held them for a long time, the young, after each ob- 



