298 



The eggs are laid in the wounds, and the egg-stage lasts exactly 

 three days. The larva was found in the following palms : — Metroxylon 

 sagiis, Arengci saccharifera, Elaeis giiineensis, and CorypJia gebanga, 

 and in addition has been recorded in Phoenix sylvcsiris and Borassiis 

 flahcUifc)'. Another breeding-place is the rubbish from the native 

 sago manufacture. The larvae like moist surroundings and are not 

 drowned by 48 hours' submersion. The damage done by a few 

 individuals is astonishing. The greatest number found in a coconut 

 palm was 42 ; in a dead sago palm 155 larvae, pupae and adults were 

 observed. The shortest larval period in the laboratory was three and 

 a half months. Under conditions approximating to those in nature 

 the shortest period was two months. There is an inactive larval 

 stage in the cocoon. This lasts 3-5 days and is followed by a pupal 

 stage of 13-15 days. After emergence from the pupa, the weevil 

 remains for 11-18 days in the cocoon. The first eggs were laid 11-21 

 days after emergence. Trapping gave an average proportion of 60 

 males to 40 females. Experiments with marked weevils showed that 

 thev can detect favourable breeding-places at 1,000 yards distance. 

 A greater distance is quite probable, and the fifty-yard estimate found 

 in the literature is quite inadequate. The maximum number of eggs 

 obtained from one female was 531. Up to 87 per cent, of the eggs 

 produced larvae. The longest period of adult life in captivit}^ was 

 107 days. The shortest life-cycle was three months, at sea-level 

 (Padang), and the longest seven months, at 780 feet (Buitenzorg) 

 under unfavourable conditions. Four annual generations are therefore 

 possible. 



The American palm weevil [Rhynchophorits palmar 11)11] in Trinidad 

 is said to be attracted by the soft tissue of palms. The author 

 had observed that fresh cut trunks of the sago palm strongly attracted 

 R. ferrugineus, and experiments were made on the trapping value of 

 this easily obtained material. Two days after felling, the fresh sago 

 trunks become attractive and remain so for 10-13 days. Pieces of 

 trunk from a palm that had already flowered remained attractive 

 for a month. As a tree dies after bearing fruit, it is worthless except 

 for such traps. The weevils fly by day, rarely at night or in the dusk. 

 Both sexes were attracted, the females averaging 40 per cent, of the 

 catches. During the experiments 501 weevils were captured in seven 

 experiments, a whole sago palm trunk being cut up and used in each. 

 As one female may lay over 500 eggs, it is obvious that this trapping 

 is advisable wherever the sago trunks have little value. The placing 

 of cages containing males with the trap trunks resulted in a higher 

 number of captured weevils, males as well as females. 



The trunk of a young coconut palm (4-6 years old), cut into six 

 pieces, served to attract the weevils for two days only. A number 

 of other experiments were made with baits. Coconut water from 

 ripe or nearly ripe nuts, ordinary alcohol, coconut toddy, acetic acid, 

 and other substances gave no results. Decaying sugar-cane M'as of 

 some use, but very much inferior to sago trunks. 



In experiments on the manner in which the weevils enter the palms 

 it was found that infestation was not effected on the healthy cortex 

 of voung or old palms. Eggs are only laid in wounds, including those 

 a month old. In old trees with hard tissues the larvae never developed ; 

 in young trees development was normal, and the trees were badly 

 damaged or died. Infestation in steps cut for climbing the palms had 

 fatal results in young trees. Infestation in fresh leaf scars failed. 



