6 FARMERS’ BULLETIN 1759. 
in extending their colonies, and usually gain entrance to buildings 
from colonies outdoors. Infestation of the interior woodwork is 
effected from underground tunnels to and up through moist or 
decayed foundation timbers, floormg, or supports of porching or steps 
set in or on the ground. 
Beams, such as joists, studding, stringers, and other foundation 
timbers in the basement or cellar, even though entirely inclosed or 
embedded in concrete, are but partially protected from attack by ter- 
mites. In the settling of the structure, or in weathering, concrete is 
Fic. 6.—Supplementary nymphal reproductive forms of the European white ant Leucotermes lucifugus; 
one king and three queens. Colorado Springs, Colo. Enlarged 10 times. (Original.) 
almost sure to crack and allow moisture and insects to enter. Fur- 
thermore, beams and joists put down in moist concrete decay rapidly 
and become exceptionally good breeding places for these insects; 
from such beams white ants carry their burrows up through the tim- 
bers to the first, second, and even third floors. 
Flooring (fig. 8) and other stationary woodwork and furniture fre- 
quently become infested when the wooden beams are laid directly 
on the earth or in moist concrete; they are often reduced to mere 
shells, the interior being completely honeycombed. Termites 
usually follow the grain when working in solid wood. 
