78 



THE COCO-NUT 



CHAP. 



required for the life-cycle of Rhynchophorus. Mr. E. E. 

 Green, Government Entomologist of Ceylon, says : 

 " I have found nearly fully grown larvae of the beetle 

 in trees under conditions that indicate that they must 

 have developed within a period of six weeks. It seems 

 possible that the insect may reach maturity in from 

 eight to ten weeks time." Banks estimates the necessary 

 time at eighteen to twenty-four months. I have found 

 numerous cocoons containing larvae, apparently mature, 

 in trees which had been cleaned perfectly and used for 

 bait ten weeks before. Vosseler puts the duration of 

 the life-cycle of Rhynchophorus phoenicis, F., at one 

 year ; the pupa rests six to eight weeks. 



The adult does not fly during the day, and apparently 

 travels, as a rule, but a short distance. All vulnerable 

 trees immediately around a badly infested one are almost 

 sure to be attacked, while those even 50 metres away 

 are comparatively safe. It is moderately attracted to 

 light, but not so strongly that any great numbers 

 can be destroyed by bonfires. It needs no food, and 

 enters a tree only to find a place to lay eggs, or a place 

 of refuge. 



The methods to be employed in fighting Rhyncho- 

 phorus follow obviously from the fact that it cannot 

 lay its eggs in sound trees, but only in those where the 

 softer tissues have already been exposed in some way. 

 Coco-nuts usually become susceptible to its attacks in 

 one of the following ways : 



1. By mechanical injury done by men. 



2. By previous attack by other insects. 



3. By injury by violent storms. 



4. By being burned. 



1. Mechanical injury is done to trees, by those who 

 think they are taking care of them, in several ways, as 

 by cutting notches in the trunk, in cutting down the 

 nuts, and by unduly clearing the crowns. While the 

 general view in English colonies has been that these 

 beetles attack the top of the tree directly, Banks thinks 

 it no less normal for them to enter through lesions in 



