Maskell. — On the Warfare against Insect-pests. 283 



carried on in them if the iusect-pests were kept down — as also 

 in coffee, which is now largely planted there. Already, before 

 Mr. Koebele's engagement, the planters had been troubled 

 with Icerya purchasi, and I may pause here a moment to give 

 you what may perhaps seem an even startling statement. In 

 the year 1891, I think, Mr. Jaeger, a resident of Honolulu, 

 wrote to me saying that Icerya was rapidly increasing there, 

 and asking me to procure for him some Vedalia to eat it. 

 Although I could not myself supply him, I was able to put 

 him in the way of getting these useful beetles, and in a few 

 months he introduced them to Honolulu. By that time, how- 

 ever, Icerya had enormously increased there, so much so that, 

 in a letter received by me only a week or two ago, I find this 

 statement : " Icerya became so numerous that it was not safe 

 to walk in the streets, as they became so slippery ; and near a 

 large burying-ground, where the ' monkey-pot trees ' were full 

 of the scale, on the side where the wind blew towards some 

 houses the people had to leave the houses because they 

 became so full of the young insects that it was impossible to 

 sleep." After the introduction of Vedalia, Mr. Jaeger says, 

 in six months a clean sweep was made of Icerya, the ladybirds 

 increasing in such numbers that in places they could be swept 

 up in heaps ; and now the Sandwich Islands have no more to 

 fear from Icerya. 



Encouraged by this success, the people of Hawaii thought 

 they might extend their efforts, and they engaged Mr. Koebele 

 to give them his time and energies with this object. Going 

 to Honolulu in 1892, he sent down to me several scale-insects 

 for identification and description ; and I was able to put him 

 on the track of some useful parasites by acquainting him with '• 

 the native country of some of these pests and their relation- 

 ships and life-histories, for particulars of this kind are great 

 helps in that direction. Some of the scales in question were 

 described or mentioned by me in my paper of 1892 (Transac- 

 tions, vol. xxv.), and others will be included in my paper for 

 the volume of 1894. Amongst them are two especially in- 

 jurious ones, which I have named respectively Pulvinaria psidii 

 (on guava and coffee) and Dactylopkis vastator (on orange and 

 a great many other trees). Both of these are probably im- 

 portations to Honolulu from Japan in the last five years. Re- 

 garding the first, Mr. Koebele, who is at present in Australia, 

 writes to me that it " attacks the coffee, and bad at that ; and 

 for miles away you could see the presence of the scales by the 

 black appearance of the guava forests." As to the second, he 

 says, " I have seen no Coccid that is so destructive to trees as 

 this species." But he goes on to say, " I have already intro- 

 duced two of the ladybirds which prey on Pulvinaria psidii, 

 and think that in a couple of years it will be rare in Hawaii ; 



