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SUMMARY. . 



The Rhinoceros beetle, though laying eggs slowly, can multiply 

 with great rapidity and as it in all places seems to kill a few coconut 

 palms, when it is unchecked the amount of destruction done may- 

 mount up to something appreciable (upwards of I — 2 per cent, in the 

 worst localities in Samoa) ; beyond the destruction there is a reduc- 

 tion of the yield in less severely attacked palms. Young palms are 

 more liable to its attacks than old ones, partly because they stand in 

 the still or moist air near the ground where the mature beetle seems 

 chiefly to fly, but more because of the greater length of relatively soft 

 tissue which they offer to attack. 



The mature beetle tunnels in palms for the sake of food, making 

 its tunnel a lair ; it usually burrows through the enfolded young 

 leaves and does not reach the heart of the cabbage and so does not 

 kill the palm : it probably lives for several months, the female steadily 

 laying eggs throughout the period, but the duration of life and the 

 continuance of egg-laying are matters of conjecture. The beetles, 

 and their grubs, shun day-light : they mate in the feeding tunnels or 

 else in the places where the eggs are laid. They sometimes fly to 

 light at night, but not with suflicient readiness for lights to be used 

 as traps. There is something about a palm attractive to them, but it 

 is not the odour of the drawn sap nor of the flowers. The opposite 

 sexes have an attraction for each other ; but the caging of the one to 

 entrap the other is only moderately effective. Eggs are laid in de- 

 caying vegetation, and when as sometimes happens they are laid in 

 living coconut stems, it may be that some decay had already been set 

 up in an old wound. The smell of decaying vegetation, particularly 

 of decaying palm stems is very attractive to them and may be used 

 for the making of traps. The eggs hatch in 10-12 days, and the grub 

 seems to require about five months for maturing ; then it pupates 

 and remains for a brief time as a pupa, emerging a beetle, it would 

 seem, within seven months of the laying of the egg, unless cold or 

 dry weather delays it. 



The grub is very thin-skinned, and requires moist food ; it can 

 live in very moist food (slush). Exposure to dry air very rapidly 

 kills it. 



The way to attack the insect is to remove its food-supply, for 

 although within the region of its natural distribution there are doubt- 

 less parasites and enemies, which do something in the way of keeping 

 its numbers down, we know nothing of them, nor are we likely at 

 present to use them to effect. Where the insect has appeared in 

 excessive numbers, the cause has been man, in most, if not in all 

 cases; usually man by putting an exceptional amount of food in the 

 way of the insect, has given it the means of unduly increasing. It 

 behoves us to keep all vegetable refuse under control both in the 

 plantations and about neighbouring tan-yards, saw-mills and villages, 

 for the beetle is not of restricted flight. Old coconut stumps and trunks 



