ENTOMOLOGY 327 



same in quarantine for a sufficient time to determine whether the 

 treatment is successful. 



Damage by powder-post insects to many kinds of articles can be 

 prevented and at the same time the material otherwise benefited by 

 treating the sapwood with linseed oil or kerosene, either by immers- 

 ing it in the oil or by applying the oil with a brush, the application 

 to be made as soon as possible after the articles are finished from re- 

 cently seasoned, uninjured stock. 



TAN BARK. 



Damage to hemlock and oak tan bark by the class of insects 

 which in some cases has been so destructive to these products in the 

 past can be easily prevented without cost, as follows : 



(1) Utilize the bark within three years from the time it is taken 

 from the trees. 



(2) Prevent the accumulation in the yards and store-sheds of 

 old bark and waste material in which the insects can breed. 



These simple methods have been extensively adopted since their 

 recommendation in correspondence and publications between about 

 1894 and 1904, and afford one of the most striking examples of the 

 value of expert information on the peculiar habits of insects and of 

 how millions of dollars can be saved without cost through a simple 

 adjustment in methods of utilization. 



UTILIZED PRODUCTS. 



Damage and loss from insect injuries to timber and other wood- 

 work in structures of various kinds, to telephone and telegraph poles, 

 posts, railroad ties, mine props, etc., can be prevented to a large ex- 

 tent through the adoption of the proper methods of management or 

 of treating the material with preservatives before and after it is 

 utilized. 



TIMBERS AND WOODWORK IN STRUCTURES. 



Injuries to timbers and woodwork in dwellings, outbuildings, 

 bridges, etc., by powder-post insects can be prevented as follows: 



(1) Use nothing but heartwood for the concealed parts most 

 liable to damage. 



(2) If it is necessary to use all or part sapwood material, attack 

 can be prevented by treating the sap portions with kerosene, coal 

 tar, creosote, or linseed oil. Facilities for future treatment can be 

 provided wherever the rough or finished woodwork is exposed, as in 

 outbuildings, bridges, etc., if care is taken to expose the sapwood 

 portions. 



(3) If the untreated timbers and woodwork in old buildings 

 show evidence of attack, the affected portions should be given a lib- 

 eral application of kerosene. 



Damage by white ants, or termites, can often be prevented in the 

 following ways: 



(1) By the use of nothing but sound wood for underpinning 

 and foundation timbers and the removal of decaying timbers from 

 old structures. 



(2) By preventing moist conditions of the wood in any part of 

 the structure and especially that in foundation timbers. 



