478 PROCEEDINGS OF THE AMERICAN ACADEMY. 



The second column under each activity gives the average number of 

 workers in the colony, the fourth and sixth the average numbers of the 

 two classes of workers (soldiers and minors, respectively) in the nest 

 during the observations on that activity. It was necessary to take 

 the average number rather than the total number, because of the death 

 of some individuals between series of observations when the whole of an 

 experiment on a colony could not be carried out at one time. In many 

 cases this was equal to the total number of individuals at the begin- 

 ning of the experiment, no deaths having occurred. The third, fifth 

 and seventh columns under each activity give the average per cent of 

 the workers as a whole and of the respective classes (soldiers and 

 minors) which took part in each activity. These were found by di- 

 viding the sum of the per cents of those which were active at each ob- 

 servation by the total number of observations, usually 150. Dots 

 signify that a particular experiment was not made upon the colony 

 opposite which the dots appear, as, for instance, opposite colony 81, 

 "feeding," "regurgitating," etc. This was usually due to the death 

 of the whole colony before the experiment on that form of activity 

 could be carried out, but in the case of " surrounding the queen " the 

 absence of records is due to the fact that most of the colonies had no 

 queen. Colonies 81, 86, 87, and 91 were Pheidole pilijh-a ; 82, 83, 

 and 84 were P. dentata ; while colony 58 was P. vinelandka. 



Of Pheidole pilifera, only one colony (8G) was tested in the matter 

 of feeding. Of all the workers, including both soldiers and minors, the 

 per cent engaged in feeding was small (0.003 per cent). In this case, 

 the soldiers did not take part at all. 



3. Regurgitating and Receiving Regurgitated Food. 



1. Methods. — As these two sets of activities are necessarily recipro- 

 cal, they were noted at the same time. At two-minute intervals the 

 number of ants of each class engaged in regurgitating food was re- 

 corded, and likewise the number of each class which were receiving re- 

 gurgitated food. As the ants were inclined when opportunity offered 

 to hide in the earth, a wet sponge, to provide both drinking water for 

 them and dampness for the atmosphere, was substituted for earth. To 

 prevent the ants from hiding in this sponge it was wrapped in cheese 

 cloth, the edges of which were securely sewed together so as to leave 

 no openings. When this was done great care had to be taken to pre- 

 vent the sponge from drying. This sponge was placed in one chamber 

 and food in the other. 



2. Observations. — Three colonies of Pheidole j}ilifera were observed 

 in these experiments. Here, again, there were very few ants (0.01 per 



