28 BULLETIN 333, U. S. DEPARTMENT OF AGRICULTURE. 



timbers are teak, greenheart, ligiram-vitse, etc. " Karri " (Eucalyp- 

 tus diversicolor) and "jarrah" (E. marginata) , of Australia, are 

 resistant although, not immune to attack by termites. 



REMEDIES. 



' LOCATION OF DAMAGE TO WOODWORK IN BUILDINGS. 



The point of emergence of the flying termites may indicate approx- 

 imately the location of the infested timbers; if the insects are not 

 observed swarming, large numbers of the dead winged adults or the 

 discarded wings will be found near by. Frass and earth thrown out' 

 of crevices through which the insects emerge are also evidence. In 

 efforts to stop further damage by termites in buildings it should be 

 realized that the numbers of these insects may be constantly recruited 

 from some undiscovered, outside central colony. The destruction of 

 the winged, colonizing adults at the time of the emergence, while ad- 

 visable in preventing the establishment of potential new colonies, is 

 of no value in eradicating the insects infesting the woodwork. 



Another indication of infestation is the presence of longitudinal 

 earthlike tubes, of small diameter, constructed on foundation timbers 

 or other woodwork, or over the surface of stone, brick, or other im- 

 penetrable foundation material from the ground to the woodwork. 

 Drenching the ground — where these tubes originate — with kerosene 

 oil will afford relief. A prompt examination of the foundation tim- 

 bers, such as beams and joists in contact with the ground, should be 

 made to determine the approximate point of entrance of the insects 

 and the extent of the damage already accomplished. It may be nec- 

 essary to tear up the flooring and other woodwork to accomplish this. 

 The foundation timbers and interior woodwork found damaged 

 should be removed and burned and the ground where they were set 

 drenched with kerosene oil. 



ROCK FOUNDATIONS AND WOOD PRESERVATIVES. 



The main point is to prevent the insects from gaining access to the 

 woodwork from colonies in the ground, either by means of substitut- 

 ing rock or concrete foundations and concrete or tile flooring in the 

 basement or by protecting the foundation timbers in contact with 

 the ground by impregnation of the wood with coal-tar creosote. 



It is very rarely possible to find and destroy the external colony, 

 and it may be necessary to replace the foundation of the buildings 

 with walls and floorings of stone, concrete, or other form of rock 

 composition, and this is the most permanent and complete preventive. 

 In the case of the National Museum buildings, the Carnegie Insti- 

 tution of Washington, and several private edifices in Washington, 



