GENERAL ACCOUNT OF MISSION TO FIJI. 



The primary object of my visit to Fiji being the investigation 

 of the economic conditions of Leaf-hopper in the sugar-cane 

 fields, I found that I could not make Suva my headquarters as 

 the nearest sugar plantation was some twelve miles away, so I 

 moved up to Rewa. 



In January, 1906, I visited Ba, on the northern side of the 

 island, and in February spent a few days at Navua, on the south- 

 west side. Rewa and Navua are "wet" districts with a rainfall 

 from no to 130 inches per year, whilst Ba is dry. I arrived in 

 Fiji at the end of one of the worst droughts that Fijians could 

 remember, the northern side of the island being very dry ; but 

 the drought broke in January and during the latter part of my 

 stay collecting was difficult on account of heavy rains and breed- 

 ing insects was made nearly impossible on account of mould in- 

 duced by the excessively damp weather. 



The Fijian sugar cane leaf-hopper {Pcrkinsiella vifiensis) I 

 found all over the island, but it does no damage, being kept in 

 check by several natural enemies. 



The most important of these are the egg-parasites, Ootetrastich- 

 us, Anagrus and Paranagrus. The first of these was introduced 

 from Fiji into Hawaii by Mr. Koebele, and the other two appear 

 to me the same as the Queensland species. In some fields as 

 many as 90% of the hopper eggs were parasitized, but in other 

 fields it was lower. Observations extending over my six months' 

 stay, and made at the various parts of the island visited, show 

 that an average of 85% of hopper eggs were destroyed by these 

 parasites. These figures are only approximate, as I have to esti- 

 mate that one Chalcid (Ootetrastichus) destroys four hopper 

 eggs, which is a low estimate. This Chalcid is more numerous, 

 and on account of destroying the whole batch of hopper eggs, is 

 of very much higher economic value than the Mymarids. 



As these parasites had already been introduced in Hawaii, I 

 did not lay myself out to send more, but only sent them, along with 

 other insects as opportunity offered. 



The parasite next in economic value is a Stylopid {Elenchus 

 tenuicornis). This I found attacking young and adults on all 

 the plantations I visited. In one field of cane about ten to twelve 



