348 Philippine Journal of Science m» 



Certain species of wood are said to be naturally highly re- 

 sistant to the termite. According to Thomas E. Snyder, forest 

 entomologist of the United States Department of Agriculture, 

 teak {Tectona grandis) from Siam and Burma, greenheart 

 (Nectandra rodiae) from South America and the West Indies, 

 peroba (several species of Aspidosperma) from South America, 

 and mahogany (Swietena mahogani) from tropical America 

 seem to be immune from the attack of the North American 

 termites. 8 Hagen also states that teak (Tectona grandis) and 

 ironwood (Sideroxylon) of India are immune from attack by 

 termites. 4 George P. Ahern, formerly director of the Philippine 

 Bureau of Forestry, states that the following woods are not 

 subject to attack by the anay, a native Philippine termite: 

 Dinglas (Eugenia bracteata Roxb. var. roxburghii Duthie) , ipil 

 (Intsia bijuga Gray), molave (Vitex littoralis Dene.), and yacal 

 (Hopea plagata Vidal). In addition to these, Cedrus deodar 

 from India, Cedrus atlantica from northern Africa, Callitris 

 glauca (cypress pine) from Queensland, Eucalyptus marginata 

 from Australia, and Erythrophloeum lim from Cochin China are 

 reported to be immune from termite attack. 



As a first step in the investigation it was necessary to prove 

 whether these so-called immune timbers are really effective in 

 preventing termite attack or not. To do this, forty-five species 

 of native and exotic woods were selected and the test carried on 

 as follows: 



Method of investigation.— -Each timber was cut into small 

 blocks of definite size, 2 by 2 by 15 inches (about 5 by 5 by 38 

 centimeters) ; hundreds of these blocks were buried in the 

 infested ground; different kinds of timbers were mingled, care 

 being taken not to group the same species in one place; from 

 time to time all the blocks were dug out for inspection, and 

 after eliminating the infested ones the others were buried again. 



Locality of the experiment stations. — Tainan, southern part of 

 Formosa; and Matsubase, Kiushiu, Japan proper. 



Materials. — The woods that were used are enumerated in 

 Table VIII. 



Result of the test at Tainan. — The ground was infested with 

 Odontotermes formosanus (Shiraki), which is very common in 

 the southern part of Formosa. The blocks were buried on 

 November 17, 1912, and the final inspection was made on July 

 15, 1913. 



'Bull. U. S. Bur. Ent. 94* (1916) 79. 

 * Monogr. Term. 10: 44, 45. 



