METHODS OF REPRESSION. 95 
destroyed by exposing the colonies with a shovel and scalding them 
with hot water or spraying them with kerosene. At the senior 
author's suggestion a number of small boxes filled with hay and trash 
were placed at various points in the orchard. When the water was 
admitted it was found that the colonies moved into these boxes in 
preference to going up the trees. They could thus be destroyed with 
one flooding instead of two, as formerly. 
It may be remarked in passing that the ditches, when pains have 
been taken to prevent the ants crossing them, have effectively limited 
the spread of the ants through the groves. This fact amply substan- 
tiates our observations, mentioned on pages 19-20, to the effect that 
colonies are never established by individual queens returning from a 
marriage flight. Were colonies established in this manner, the areas 
of infestation would not be sharply defined, nor would ditches retard 
the dispersion of the ants from heavily infested centers. 
EXPERIMENTS WITH WINTER TRAP BOXES- 
The success which had followed experiments at Baton Rouge in 
getting the ant colonies to concentrate during the winter in boxes 
of decaying vegetable matter induced us to try the same plan in 
an infested orange grove. Accordingly in November, 1910, a large 
number of boxes, each 2 by 2 by 3 feet, of rough lumber, were made 
and distributed throughout the infested block. Each was filled, 
during the latter part of October, with a mixture of cotton seed and 
dead grass. The top of each box was left exposed to the weather, 
so that rain would enter to moisten the contents and start decay. 
An examination of the boxes on November 16 showed that many 
colonies had entered them, but that many still remained in the 
ground. To afford the ants less natural protection the orchard was 
cultivated to remove the standing grass and weeds. In January, 
1911, the authors again visited this orchard and found all boxes 
filled almost to overflowing with enormous ant colonies. Each box 
contained workers by the hundreds of thousands and queens by the 
hundreds. A close examination in various parts of the orchard 
showed, however, that not all colonies had entered the boxes. Some 
few colonies had remained in their underground nests, particularly 
where grass or weeds had been overlooked in the November cultiva- 
tion and where, therefore, these colonies were afforded more protec- 
tion than in the plowed portions. Whether the already crowded 
condition of the boxes had prevented other colonies from entering 
them we could not determine. 
Experiments were now undertaken in destruction of the colonies 
in the boxes. Metal covers had already been constructed for con- 
fining gases in the trap boxes. (See PI. XII.) Experiments were 
