METHODS OF STUDY. 



33 



difficult to attacli 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 PI. II.) 



The cage proper is supported on a platform (1) which in turn rests 

 firmly upon a standard (i) having a base (4). The platform must 

 have its upper surface perfectly level and it must remain so for an 



Tig. 7. — Artificial formicary or cage used in studying the Argentine ant: /, Supporting platform; S, stand- 

 ard; 3, cage proper, made of glass and leather, containing earth; 4, base; S, 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 | 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 



