METHODS OF STUDY. 
33 
difficult to attach one piece of glass to another firmly. Wooden 
strips present the disadvantage of quickly decaying and of warping, 
no matter what glue or cement is used to hold them in position. Since 
it is sometimes desirable to place moist earth in the cages, or to add 
moisture from time to time, a waterproof cement is most desirable 
for attaching the glass plates to the leather strip. The space between 
the glass plates is filled with finely pulverized earth after completion 
and drying of the cage, and in this the ants are permitted to burrow 
and construct galleries as they please. (See PL II.) 
The cage proper is supported on a platform (1) which in turn rests 
firmly upon a standard (2) having a base (4)- The platform must 
have its upper surface perfectly level and it must remain so for an 
. stand- 
Fig. 7.— Artificial formicary or cage used in studying the Argentine ant: /, Supporting platform; 
ard; 3, cage proper, made of glass and leather, containing earth; 4, hase; 5, cover. (Senior author's 
illustration.) 
indefinite time, otherwise the ants will take up their abode between 
the cage and platform rather than in the cage itself. The platform is 
therefore made of two pieces of even, seasoned cypress J inch thick, 
screwed together with numerous screws and with the grain of the 
two pieces at right angles to each other. On this platform the cage 
rests without fastenings of any kind. The cover (5) is constructed of 
two pieces of cypress in the same manner as the platform, but in 
addition has an iron handle attached to its upper surface and has a 
piece of felt glued to its under surface, so that, when it is placed upon 
the cage proper, all light is excluded except at the entrance. The 
cover is of the same outside dimensions as the cage itself. To insure 
the platform remaining level it is often necessary to make the base 
75508°— Bull. 122—13 3 
