S 2 FIELDE. [VOL. II. 



be fastened to the glass, as the latter must sometimes be raised 

 in order to get a view of the ants from below. 



o 



The walls stand half an inch from the edges of the base-pane, 

 for the greater security of the superstructure when the nest is 

 being lifted. The walls are built of strips of "double thick" 

 glass, half an inch wide, two horizontal layers in every wall 

 giving a perfectly level top. Apertures three-eighths of an 

 inch wide are left in the walls at points marked a on the plans. 

 These apertures admit the end of a three-eighths-inch glass 

 tube, which may be used as a safe bridge between nests when 

 ants are to be made to pass from one nest into another. When 

 not in use, the apertures are closed with plugs of cotton. The 

 outside of the walls, after thorough drying, are painted black, 

 to secure within the nest the darkness in which ants like to 

 keep their young. 



The main partitions in the ant-dwelling take part with the 

 walls in the support of separate roof-panes, and they are there- 

 fore twice as wide as are the walls. Passageways (marked m 

 on the plans) permit the ants to go from one room to another, 

 as is necessary when a room is to be cleaned. The admission 

 of strong light will insure the removal of the ant family to the 

 darkened chamber adjoining. The passageways may be from 

 one-fourth to one-half inch in width, and they should be cov- 

 ered with very thin glass, well glued on. 



The tops of the walls and main partitions are exactly cov- 

 ered with coarse Turkish toweling, cut in strips twice as wide 

 as the base on which it lies, and doubled so that its raw edges 

 meet in the middle of the glass it doubly covers. The under 

 layer of the toweling is glued to the glass, and it performs the 

 double office of keeping the ants within the nest and of admit- 

 ting sufficient fresh air for their breathing. Just over the pas- 

 sageways the toweling is left free, so that it may there be lifted 

 for observation of what is within. After the toweling is laid 

 on, the rooms have a uniform depth of less than half an inch, 

 and a hand lens can be focused upon any of their inmates. 

 The toweling being elastic and level, the roof-panes, of thin, 

 clear glass, lie closely upon it. They are not fastened down. 



The roof-panes reach the center of the main partitions and 



