470 PROCEEDINGS OF THE AMERICAN ACADEMY. 



large predominated at the other. The several series fell into the fol- 

 lowing order, beginning with those in which the smallest sizes predom- 

 inated : (1) tending the young, (2) foraging, including ants actually 

 carrying food, - — which was done neither by the very large nor the 

 very small, — (3) surrounding a very young queen, carrying other 

 ants, and being carried by other ants (the ants in these series being of 

 about equal oize), (4) building, (5) responding to external disturbances. 

 It should be stated, however, that the three activities listed under 3, 

 as well as that of actually carrying food, had only a few individuals in 

 each. Of the other activities, tending the young was exhibited by 

 114 individuals, foraging by 96, building by 42, and responding to 

 disturbances by 56. A series was also made of 74 individuals which 

 were tending the young under excitement, i. e. when their nests were 

 disturbed ; these ants were, on the whole, much larger than those 

 which were collected under normal conditions of tending the young. 

 To watch this activity under normal conditions is more difficult than 

 to watch several of the other activities ; but in some colonies the ants 

 brought the young near openings in the nests, or in carrying them from 

 one part of the nest to another, had to pass exposed places, so that I 

 was thus able to observe and capture them. I was also able on some 

 occasions to open the nest suddenly enough to see ants tending the 

 young before they became disturbed. Although from the shape of the 

 heads of all sizes of individuals one would not expect to find any special- 

 ized guards, such as are found in Colobopsis (Lubbock, '82 ; Forel, '74 ; 

 : 03, p. 83 ; : 05, pp. 453-454 ; Escherich, : 06, p. 46 ; "Wheeler, : 04% 

 : 10, pp. 184, 211-212), nevertheless I made an examination to see if 

 there were any indication that special guards existed. This species 

 does not appear to guard the entrances in any way, but, with the 

 exception of those individuals which are going in and out, all individ- 

 uals are more apt to stay quietly huddled together in chambers within 

 the nest. By trimming off little by little the decayed wood of the 

 nest, along the passages, working from the outside in, and taking 

 great care to create no disturbance, I have succeeded in making this 

 observation repeatedly. No queens were engaged in any of the activ- 

 ities, probably because here there were a sufficient number of workers 

 to attend to the needs of the colony. 



In order to see how much influence the size of the colony had on the 

 sort of individuals participating in certain occupations, I noted, at the 

 time the ants were collected, the size of the colony. This had to be 

 estimated roughly, and when statements of the size of a given colony 

 were recorded on ditferent days, these separate estimates were consid- 

 ered in making up the final estimate ; colonies were classed as very 



