METHODS OF COLLECTING A.\D STUDYING AXTS. 553 



of the strip of towelling meet in the center of the underside of the 

 wadding. The wadding is cut to the same width as the wall or the 

 partition. The towelling is just twice the width of the wadding, and 

 its edges are basted evenly together, making a cushion of even thick- 

 ness. It serves the double purpose of admitting air into the nest and 

 preventing the escape of the ants between the roof and its supports. 

 It is held taut and is made level ; it is fitted snugly at the corners, 

 exhibits no ravelings to afflict the ants and is firmly glued to the glass 

 beneath it. When a cushion becomes soiled by long use of the nest, 

 the glue may be softened by soaking and the cushion may be removed 

 and be replaced by a new one. The ends of the cushions are fringed 

 out a half inch or more, and are left open so that the enclosed wadding 

 may be adjusted to present a perfectly level surface. 



' There is a glass roof-pane for each room in the nest. The glass 

 is thin ; extends to the middle of the partition and to the outer edges 

 cf the walls on which it rests; prevents the exit of the ants and permits 

 observation of their behavior. The glass may be without color, or it 

 may be of a red or orange tint that will partially exclude ultra-violet 

 rays of light. Ants perceive only such rays of light as are of short 

 wave-length, and, by use of a spectroscope, a glass roofing may be 

 selected which renders the ants visible within the nest, while it protects 

 them from such light-rays as they instinctively shun. If such glass is 

 used for roofing 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 ants' 

 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 forthnight. Sponge-cake, merged in a little honey or molasses, 

 banana, apple, mashed walnut, and the muscular parts of larvae of 

 insects are among their favorite edibles. Food is constantly attainable 

 in the nest, but is introduced in tiny morsels that it may not vitiate 

 the air. 



' Since moisture encourages the growth of mould, 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 



