INSECT ENEMIES OF WESTERN FORESTS 



207 



c y 



Figure 99. — Carpenter ants and their work: A, Worker; B, queen with wings 

 shed; C, queen with wings folded; D, excavations in wood. Natural size. 

 (Furniss.) 



seem to fail. The first precaution is to prevent the ants from 

 gaining access to foundation timbers. Where timbers are placed 

 on solid foundations away from contact with the ground, the 

 chance of carpenter ant attack is greatly minimized but not 

 always prevented. The best preventive is to impregnate founda- 

 tion timbers thoroughly with creosote. 



After a piece of timber has become infested, the colonies of 

 carpenter ants can be destroyed by dusting with 5-percent chlor- 

 dane, 4-percent rotenone, 10-percent DDT, sodium fluoride or 

 arsenical dust; or injecting liquid carbon disulfide or orthodi- 

 chlorobenzene into the nests. The dusts are probably the most 

 satisfactory, for the ants will track through them and carry them 

 to all parts of the nests, whereas the liquids and gases are often 

 blocked by the tortuous, partly frass-filled cavities. When house 

 timbers become badly infested, it is often necessary to tear them 

 out and replace them with timbers treated with creosote. All 

 decaying wood in the vicinity of the buildings, such as old logs, 

 etc., should be cleared away. 



LARGE CARPENTER BEES 



Certain species of large bees (Xylocopidae), resembling 

 bumble bees, excavate large cylindrical tunnels in dry bark or 

 wood in building their nests. Often they merely take over the 

 galleries of other insects. Their tunnels, especially where several 

 colonies of bees build nests close together, may weaken building 



