82 THE NATURALIST IX NICARAGUA. [Ch. V. 



below. The great care they take that the pieces of 

 leaves they carry into the nest should be neither too dry 

 nor too damp, is also consistent with the idea that the 

 object is the growth of a fungus that requires particular 

 conditions of temperature and moisture to ensure its 

 vigorous growth. If a sudden shower should come on, 

 the ants do not carry the wet pieces into the burrows, 

 but throw them down near the entrances. Should the 

 weather clear up again, these pieces are picked up when 

 nearly dried, and taken inside ; should the rain, however, 

 continue, they get sodden down into the ground, and are 

 left there. On the contrary, in dry and hot weather, 

 when the leaves would get dried up before they could be 

 convej^ed to the nest, the ants, when in exposed situa- 

 tions, do not go out at all during the hot hours, but 

 bring in their leafy burdens in the cool of the day and 

 during the night. As soon as the pieces of leaves are 

 carried in they must be cut up by the small class of 

 workers into little pieces. I have never seen the smallest 

 class of ants carrying in leaves ; their duties appear to be 

 inside, cutting them up into smaller fragments, and 

 nursing the immature ants. I have, however, seen them 

 running out along the paths with the others ; but instead 

 of helping to carry in the burdens, they climb on the top 

 of the pieces which are being carried along by the middle- 

 sized workers, and so get a ride home again. It is very 

 probable that they take a run out merely for air and 

 exercise. The largest class of what are called workers are, 

 I believe, the directors and protectors of the others. They 

 are never seen out of the nest, excepting on particular 

 occasions, such as the migrations of the ants, and when 

 one of the working columns or nests is attacked ; they 



