Ill 



DISEASES AND PESTS 



65 



his hole in the tree. The thorax has a large concave 

 area in the front, and back of this a point which is 

 sometimes quite prominent in males. The hard wings 

 are finely striate lengthwise, and do not quite cover 

 the abdomen. The legs are hairy. 



The egg of Oryctes is not positively known except 

 from specimens dissected from the females. These 

 specimens are 3*5 mm. long, and 2 mm. in diameter, 

 being a perfect ellipse in outline. The total number 

 of eggs deposited by one female is probably not more 

 than two dozen. 



Beginning at the size of the egg, the larva grows 

 until it sometimes reaches a length of considerably 

 more than 1 decimetre and a diameter of usually not 

 more than 1 centimetre. The head of the larva is 

 black, and the body, which is made of thirteen more or 

 less indistinct segments, varies in colour from dull 

 white to brownish yellow. There are no eyes. The 

 front three segments of the body are provided with 

 legs. The entire body is wrinkled, soft and fleshy, 

 smooth in spots, and in spots bearing fine spines. It 

 is ordinarily found bent downward in the same general 

 form as the grub of JRhynchophorus. But, unlike the 

 larva of Rhynchophorus, it is not greatly thickened 

 posteriorly. There is no satisfactory and definite in- 

 formation as to the length of life of a larva. According 

 to various authorities, it is usually from eighteen to 

 twenty -four months. Vosseler fixes the life of the 

 larva of the species he studied A at least one year. 



There is likewise no general agreement as to whether 

 or not this larva is injurious to the coco-nut tree. It 

 lives without question in the decaying wood of the 

 coco-nut ; and as young larvae are frequently found 

 in decaying parts of the standing trunks, there is no 

 reasonable doubt that the eggs are laid in these places. 

 I have never seen the larva of the black beetle in any 

 part of a coco-nut trunk which was not considerably 

 decayed, and am therefore inclined to believe that 

 these larvae do not channel the way through the 



