32 THE ARGENTINE ANT. 
METHODS OF STUDY. 
When the study of this ant was undertaken, two requisites presented 
themselves — a type of artificial formicary in which continuous obser- 
vations could be made and individuals kept track of from the time of 
egg deposition until the adult stage was reached, and some method 
by which all individuals of a colony could be confined to their own 
formicary. 
Space need not be taken to describe the types of artificial formicaries 
which were not successful. 
The Janet cages proved successful only in the case of very large 
colonies, but in these the multiplicity of individuals made accurate 
observations impossible. It may be remarked that this type of cage 
is excellent for studying the community life as a whole and for making 
experiments with poisons or with parasitic fungi or bacteria. 
Cages totally inclosed were not successful, for the reason that the 
ants, when deprived of the privilege of leaving their nest, failed to act 
in a normal manner. 
The cage finally adopted was, with modifications, the one described 
by Sir John Lubbock on pages 2 and 3 of his classic work. 1 This 
consists essentially of two glass plates containing between them a 
layer of pulverized earth in which the ants may, burrow at their 
pleasure. Considerable difficulty was experienced in getting the 
glass plates the proper distance apart; if too far apart the ants could 
make burrows which were not open to observation, and if too close 
together insufficient room was afforded the queen in which to stand 
and walk upright. As the queen is about twice as tall as the worker, 
it seemed for a tune that a suitable cage could not be constructed. 
After repeated trials, however, it was found that if the space between 
the glass plates were made exactly 1.75 mm. the queen would have 
sufficient room and the workers could not construct invisible galleries. 
This type of cage and its supporting stand are well illustrated by 
figures 7 and 8. Figure 7 shows the several parts of the cage: 3 is the 
cage proper, consisting of two plates of glass held uniformly 1.75 
millimeters apart by strips of leather at all four edges, a door or open- 
ing being left at one corner. (See fig. 9.) Old negatives, the films 
removed with caustic soda, have been found the most desirable for 
making these cages, both because such glass is remarkably clear and 
free from imperfections and because it is of uniform thickness. The 
size of the cage may vary from 3^ by 4| up to 8 by 10 inches or even 
larger. Leather was found more satisfactory for making the edges 
of the cage than either glass or wood. The strip of leather between 
the glass margins is about i inch in width. It is extremely difficult 
to find a strip of glass uniformly 1.75 millimeters thick and it is also 
i Avebury. Ants, bees, and wasps. 1881. 
