84 FIELDE. [VOL. II. 



project one-fourth of an inch beyond the walls. All the rooms 

 except the food-room have an outer roofing of thick dark 

 blotting paper, which should be lifted only when actual study 

 of the ants is proceeding. 



In the rooms numbered i the ants have, as in the Janet 

 nests, a chance to range in the light and to seek food; of which 

 it is well to put in the smallest sufficient quantity and several 

 kinds. If the ants are made to move into the darkened food- 

 room, leaving the other rooms free for cleaning, the passage- 

 ways (m) may, during the cleaning, be plugged with cotton. 



In room 3 a soft, fine sponge, clean and wet, and less than one- 

 fourth of an inch thick, should nearly cover the floor, leaving a 

 passage all around it next the walls. This furnishes drink to 

 the ants and moisture to the air of their dwelling. If the ant 

 young are in the egg or the larval stage, or if the temperature 

 is high, the floor of room 2 should likewise be covered with 

 wet sponge ; but if the young are in cocoons, or if the temper- 

 ature is very low, then room 2 should have a layer of wadding 

 instead of sponge. The ants generally choose damp places for 

 the eggs and larvae, and dry places for the cocoons or pupae. 



The screens (marked />) are substitutes for the ant-runs used 

 in the ground, and they gratify the disposition of the ant to 

 keep close to cover in going about in the nest. They are 

 made in the same way as are the walls, but are only one-fourth 

 of an inch thick, and are not topped with toweling. 



The A nest, with base 6*/> X 6 inches, is designed for a 

 colony of very small ants, or for a few large ants. The B 

 nest, with base 10 X 6 inches, affords a home for a somewhat 

 larger family. The C nest, 16^ X 6 inches, can be used for 

 a multiplying and dividing colony, or for observing the activi- 

 ties of restless species. The ants should never be greatly 

 crowded in their habitation. 



The ants in my nests appear sleek and healthy. I have 

 found these nests easier than others to keep free from the 

 molds that grow from particles of food that the ants convey 

 from the food-room to every other part of their nest. These 

 nests also lend themselves readily to experimental uses in 

 studying the instincts of their occupants. 



