~ 
to the tubers as having the form of scars or pits covering the surface, 
the pits varying in shape from irregular holes to long, irregular excava- 
tions sometimes extending far into the potato, but commonly to a 
depth of from an eighth to a fourth of an inch. In all cases these pits 
are more or less overhung and covered by the dead and dying skin, and 
are also lined with the cellular tissue of potato, showing that the insect 
cares most for the starch and water of the tuber. Such damage may 
occur not only in soil rich in vegetable matter but also in newly cleared 
soil or soil containing the loose and decayed portions of trees, and in 
the instance cited above was in soil from which an old apple orchard 
had recently been cleared. 
PREVENTIVES. 
White ant infestation of houses is probably always from an outside 
source. The queen chamber and breeding center of the colony may be 
and usually is remote from the building, but the workers construct 
minute galleries or tunnels through the ground and go long distances in 
search of moist and decaying wood. Their entrance to buildings is 
gained through some of these soil channels by way of wooden beams or 
joists sunk in concrete in the foundations of the buildings, or the sup- 
ports of porches or other parts of the edifice which come in contact with 
the soil. The fact that the beams or joists of the basement are entirely 
inclosed or imbedded in concrete is only a partial protection. In the 
settling of the house concrete is almost sure to crack, allowing avenues 
of ingress, and the beams and joists put down in the moist material 
soon partially decay and become exceptionally good breeding places; 
from such beams the white ants carry their burrows up through the 
timbers to the first and even second floors. To be on the safe side, 
therefore, the foundations of buildings should be entirely of brick, stone, 
or concrete, including the basement floor, and especially should this 
method of construction be followed in tropical and subtropical regions. 
In the case of old buildings not constructed in this way considerable 
protection can be gained by surrounding them with clear spaces and 
graveled or asphalted walks, and looking after the prompt removal of 
any decaying stumps or partially rotted posts that may be in adjacent 
grounds. Complete dryness is an important means of rendering build- 
ings safe from attack. Books and valuable documents should not be 
packed away in unventilated chambers where they may become moist 
and moldy, and are then particularly subject to attack by white ants, 
which are very likely to be present in old buildings even though their 
work has not been sufficient to bring them into special notice. 
Impregnation with creosote renders wood comparatively immune 
from the attacks of white ants, and in regions where injury is to be 
anticipated it would be well to use wood so treated wherever it comes 
in contact with the ground. A heavy coating of foundation timbers 
with tar is often resorted to, and this protects the wood as long as the 
AG—12 
