490 PROCEEDINGS OF THE AMERICAN ACADEMY. 



nests and other apparatus, except for slight differences in the number 

 of observations or in the length of time of the observations. I had no 

 opportunity for studying these ants by the other methods used on 

 P. pilifera. 



2. Observations. — Since the conclusions for these two species in the 

 main closely resembled those for P. pilifera, I have considered them 

 merely as a control, and I shall give only the points in which they dif- 

 fer from P. pilifera. The numerical values are given in Table VII. 



I. Pheidole dentata. 



1. In Pheidole dentata, though the minors were more active in re- 

 gurgitating, as also in receiving regurgitated food, soldiers appeared 

 to take some part in receiving regurgitated food. 



2. Occasionally soldiers were seen carrying larvae. 



3. No soldiers were observed carrying other ants, and only minors 

 were carried. 



4. Only minors ate meal-worms. Both classes ate honey. 



5. No soldiers and no minors were seen to crush, break, or eat grass- 

 seed. This is what we should expect, since Pheidole dentata is a purely 

 carnivorous species. 



II. Pheidole vinelandica. 



1. Surrounding the Queen, (a.) Methods. — This was the only spe- 

 cies in which I had a colony containing a queen. The ants of this 

 genus have, like other ants, a tendency to gather in groups around the 

 queen. The number of ants of each class sharing in this grouping 

 was noted once every five minutes. To keep the ants from secret- 

 ing themselves under the sponge, thus making observation difficult, the 

 sponge was removed. There was food in one chamber. 



(b.) Observations. — Only 41 observations were made on the colony 

 of P. vinelandica, because the queen died before further observations 

 were possible. The proportion of workers surrounding the queen was 

 somewhat higher (12.4 per cent) than in any of the other activities. 



In this case both classes shared in the activit)'', but the minors were 

 more active than the soldiers (13.4 per cent > 11.9 per cent). 



2. Though the soldiers, when confined in artificial nests, seemed 

 more active in feeding, the minors of this species appeared to me to be 

 much more numerous around the natural nest in the field, even in pro- 

 portion to their numbers in the colony. If more than one colony had 

 been accessible at the time of the experiments in the artificial nest, the 

 results with this species might have resembled those with the other 

 species more than these records show. There are two possible expla- 



