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ON SOME ANIMAL PESTS OF THE HEVEA RUBBER TREE. 



By E. ERNEST GREEN, F.E.S., F.Z.S., 

 Late Government Entomologist, Ceylon. 



[ABSTRACT.] 



The paper describes such animal pests of Hevea as have 

 come under the writer's personal observation in Ceylon, and 

 briefly notices other pests of the plant that have been recorded 

 by various observers in other countries. 



Such records are remarkably few, and it may be assumed that 

 the Hevea tree is still exempt from any serious or widely spread 

 animal pests. 



This comparative immunity may be due partly to the pro- 

 tective nature of the viscid latex that exudes profusely when a 

 healthy tree is wounded, and partly to the small number of 

 years during which the plant has been under cultivation. 



Where possible, recognized methods of control have been 

 indicated. 



[DISCUSSION.] 



Mr. G. STAFFORD WHITBY : Mr. Chairman and Gentlemen 

 With reference to the author's remarks on the function of 

 latex, which is of particular interest to myself, I am very much 

 inclined to agree with his position that one, at least, of the 

 functions of latex is that it serves as a protective agent against 

 the attacks of insects. In that connection I might draw atten- 

 tion to one fact which is not generally appreciated, and that is 

 that the latex, as we are acquainted with it on the estates 

 that is, latex obtained from the trees by regular tapping after 

 wound response has set in is very different in its tendency to 

 coagulate from the latex which exudes when a Hevea tree is 

 first punctured. In the latter case the latex coagulates almost 

 instantaneously, but afterwards the latex may, and in fact 

 does, remain in a liquid condition for several hours ; and it 

 is the latex present in the tree before any tapping has gone on 

 that we have to consider in respect of the function of latex in 

 regard to insect defence. Of course, I do not think that is 

 the prime function of latex, but I certainly think it is a 

 function. I was given a very interesting instance on that 

 point some time ago by a planter who found that some of the 

 tobacco pests got on to his rubber trees, but they were never 

 able to get inside. They were always stuck there as soon 

 as they had made an incision; the latex exuded, and coagulated, 

 and kept them there. There is one other point I might perhaps 



