PORTABLE ANT-NESTS. 21 7 



ants visible within the nest while it protects them from such light- 

 rays as they instinctively shun. 1 If such glass is used for roof- 

 ing the nest, the ants will behave as if in the darkness where they 

 habitually live. 



An outer roofing of blotting-paper makes the interior of the 

 nest wholly dark. The food-room should be light, as it represents 

 the ant's outside world. 



When any room in the nest requires cleaning, it is covered 

 only with transparent glass, and then the ants withdraw from it 

 with their young into a dark room, which may in its turn be 

 made light. 



The food-room is dry, and in cool weather requires attention 

 but once a fortnight. Sponge-cake merged in a little honey or 

 molasses, banana, apple, mashed walnut, and the muscular parts 

 and larvae of insects are among their favorite edibles. Food is 

 constantly attainable in the nest, but it is introduced in tiny 

 morsels that it may not vitiate the air. 



Since moisture encourages the growth of mold, no water is 

 put into the food-room. But ants often drink, and they require 

 a humid atmosphere. All other rooms than that allotted to 

 their food are made humid by laying a flake of sponge on the 

 floor and keeping the sponge saturated with clean water dropped 

 twice a week from a pipette. The proportion of the floor which 

 is covered by the sponge depends on the degree of moisture in 

 the soil usually chosen as the habitat of the species. The sponges 

 are kept clean by weekly washing and an occasional immersion 

 in alcohol. Sponges of fine tough texture render best service, as 

 they offer no apertures where the ants may conceal their eggs. 

 The flake of sponge is so thin as to permit the ants to pass 

 between it and the roof-pane. 



The completed nest is less than half an inch or thirteen milli- 

 meters in its interior height, and does not exceed three fourths 

 of an inch or two centimeters in its exterior height. A low-power 

 lens is easily focused upon the ants within the nest. 



During four years of experimental work with ants, I have 

 found that the nests whose bases are represented in the drawing 



1 " Supplementary Notes on an Ant," Adele M. Fielde, Proceedings of the Acad- 

 emy of Natural Sciences of Philadelphia, June, 1903, p. 492. 



