690 



A Tree-Strangling Fungus. [feb., 



a small number of specimens would almost at once be made up 

 for by this fact. 



As regards the general question whether the introduction is 

 desirable for other reasons, it should be remembered that the 

 natural animal and vegetable inhabitants of a particular region 

 form an assemblage in which there is a natural though very 

 complex balance, and it is interference with this that usually 

 causes economic difficulties. Attempts to remedy this trouble 

 by random introductions always fail, and it may be stated as a 

 rule that introductions of the kind proposed are generally 

 regretted subsequently, and frequently cannot be remedied. 



If it be decided to try and check this fly in Bermuda, it will 

 be necessary to discover its natural history thoroughly, and then 

 to find out in what parts of the world it lives without being 

 injurious, to discover what there keeps it in check, and intro- 

 duce this into Bermuda. 



These observations were communicated to the authorities in 

 Bermuda, and, as stated above, it is in this direction that the 

 Government of Bermuda are now seeking a remedy for this 

 .pest. Some instances in which this method appears to have 

 been attended with success in the United States were mentioned 

 in last month's Journal (p. 623). 



It may be mentioned that that this fly {Ceratitis capitata) 

 occurs in Great Britain, but it is not thought that there is any 

 probability of its becoming injurious to fruit grown out of doors 

 here, though it might do so any time if it were to get into glass- 

 houses where fruit is grown. At present it is very rare in this 

 country. 



This fungus {Thelephora lacinaia) has long been known as a 



destructive pest to young trees of various kinds. Quite recently 



some hundreds of ash saplings were killed 



A Tree- by j t> The fungus is not a parasite ; that 



Strangling . . ' , . ' , 



Fungus. 1S > !t does not penetrate the tissues of the 



plant it attacks, but causes death by 



strangulation. The fungus is most abundant on sandy heaths, 



where it forms large patches of a dark brown colour on the 



ground ; these patches consist of several overlapping thin plates 



