TUANSACTIONS OF SECTION D. Gil 



The object of the present note is to cite an illustration of artificial introduction 

 on a large scale, which has already been productive of great good. A successful 

 attempt of this kind has been made by mo in the case of Microyaster (/lomeratus, 

 which, after several futile efforts, was introduced from Europe and established in 

 the United States in 1885, and which has now become so widely distributed as to 

 raise the question of its previous existence there. This Microgaster is one of tlie 

 commonest parasites of tlie European Cabbage Worm {Heris rapcc), which got a 

 foothold in America, without its European enemies, about the year 1859, and 

 which rapidly spread over the States and parts of Canada with disastrous results 

 to the cabbage crop. 



The case to which I would particularly allude is, however, far more important 

 and satisfactory. Orange cultui'e has become a very important industry in Southern 

 California. The orange groves there have suffered for some years from the attacks 

 of several insects, but particularly of a very pernicious scale-insect, Icerija purchasi, 

 Maskell. This is one of our largest Coccids, and from its habits and characteristica 

 very difficult to overcome. It does a great deal of damage, not only to the orange 

 and other citrous fruit-trees, but to many other cultivated plants. The damage 

 has become so serious during the past few years that many orange growers have 

 abandoned their groves, while the cost and trouble of protecting these by the use 

 of insecticides have always been great even where successful. After careful 

 researches, I ascertained that the msect was, without much question, a native of 

 Australia, and had been artificially introduced net only into Southern California 

 but also into Cape Colony in South Africa, and probably into New Zealand ; also 

 that in its native home it rarely did serious damage, being kept in cheek there by 

 various natural enemies and parasites. Some attempt was made, through cor- 

 respondence with Mr. Frazer Crawford, of Adelaide, to introduce one of the parasites 

 by mail in 1887. Specimens were received alive, and liberated at Los Angeles under 

 confinement ; but no positive evidence was obtained of multiplication or colonisa- 

 tion. Special eflbrt and introduction on a larger scale seemed necessary. Last 

 autumn and winter, in connection with the Commission appointed to visit the Mel- 

 bourne International Exposition, and through the State Department, I was able to 

 send one of my field agents, Mr. Albert Koebele, to Australia, with instructions to 

 study these natural enemies and to send living specimens to California. The prin- 

 cipal facts have been recorded in my last annual report as Entomologist of the 

 United States Department of Agriculture, and in late numbers of ' Insect Life,' a 

 monthly bulletin published under the auspices of the Entomologist and his assist- 

 ants. Without going into detail, I may say that Mr. Kcebele's mission has been 

 eminently successful, and that we have succeeded in introducing alive not only the 

 most important of the parasites, an interesting Dipteron {Lesfophonm icenjo', 

 Williston), but also several predaceous species, and particularly certain ladybirds 

 (Coccinellidaj). These were brought over last winter and spring', have become well 

 acclimatised, and are now spreading and multiplying at a rapid rate. The latest 

 reports which I have received from California are to the ettect that one of the 

 commoner ladybirds, but recently described, namely, the Vedolia cardinaUs, and 

 another (lately described by Dr. D. Sharp as Scymnus fagns), are multiplying 

 and spreading in a most satisfactory manner. The consignments from Australia 

 were received at Los Angeles by Dr. D. W. Coquillet, another of the agents of the 

 Division. 



The first consignment of the Vedolia was received November 80, 1888, and 

 numbered 28 living specimens of larvae, pupae, and beetles ; the second consign- 

 ment was received December 29, and contained 45 specimens in their difl!erent 

 stages ; and the thu-d consignment of 56 specimens was received January 24 of 

 this year, making in all 129 specimens, which were placed under tent. From the 

 very first these Coccinellidae throve and played havoc with the Iceryas. By the 

 latter part of April they had increased to such an extent that it was deemed 

 advisable to send out colonies to different parts of the State, and up to date of my 

 last advices, the beginning of June, over 4,000 specunens had been sent to various 

 parties who had applied for them, while there were fully 2,000 specimens still 

 remaining where colonised. 'These 6,000 individuals,' writes Mr. Coquillet, 

 looy. ij T 



