342 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



ticularly on the leeward side of the island, that it was even difficult 

 to get eoeoanuts to drink, and of course no copra was exported. 



The insect attacks all parts of the tree, except the roots and old 

 trunk, in all stages of its growth. The first few leaves of the young 

 plant are often completely covered on the underside with the scales, 

 causing them to turn a characteristic yellow color and usually killing 

 the young plant unless relief comes. On the older trees all parts of 

 the leaves may be infested, the flower-spike is usually well covered and 

 the husk of the nut is often so completely covered that it would seem 

 impossible for another insect to find lodgement. 



On some parts of the island I found many of the trees thus covered, 

 some of the younger ones dying, the older ones having no nuts, but on 

 most of the plantations the scale seems to be disappearing at a very 

 rapid rate. Trees that three years ago bore no fruit are now in fine 

 foliage and bearing their full quota of nuts. The planters say that 

 this change was brought about by different weather conditions, but 

 my studies there show that the primary cause of this sudden change 

 was the introduction and development of the chalcid parasite Aspid- 

 iotipJiagns citriniis Craw (identification kindly confirmed by Doctor 

 Howard). Whether the parasite was introduced with the scale and 

 did not find conditions favorable for its development until the scales 

 were very abundant or whether it was introduced later, w'e could not 

 tell, but it is there in immense numbers now. On some trees 50 to 75 

 per cent of the scales were parasitized and on many others practi- 

 cally all the scales were dead, but I could not find indications of the 

 parasites' work on all of them. As the parasite may sometimes escape 

 between the upper and lower scales instead of making the character- 

 istic round hole in the upper scale, it is not always easy to tell by 

 simply examining the scale whether the insect has been killed by the 

 parasite or not. Many of the dead insects under scales that show no 

 signs of the parasite having issued will exhibit unmistakable signs of 

 its work when they are examined with the microscope. On a badly 

 infested leaf I have seen as many as ten adult parasites within a 

 radius of 3 or 4 inches walking about over the scales, stopping now 

 and then on one, presumably to deposit an egg. 



I have seen specimens of this scale more or less badly parasitized 

 from Tahiti, Morea, Titioroa, Kaiatea, Tahaa Huaheine and Flint 

 Island. As the parasite is already so well distributed the only recom- 

 mendation made to the planters was that they introduce it into groves 

 where it does not seem to be present or occurs as yet in small num- 

 bers. I believe that, under normal conditions, the parasite will soon 

 have this scale so well under control that it will no longer be a men- 

 ace to the trees. 



