390 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



FURTHER NOTES ON THE BREEDING OF THE TACHINID 

 FLY, PARASITIC ON THE CANE BEETLE BORERS 



By J. F. Illingworth, Ph.D., Professor of Enlomology, College of Hawaii, 



Honolulu, T. H. 



On April 21, 1913, I signed an agreement with Dr. Harold L. Lyon, 

 who was acting as agent for the Colonial Sugar Refining Company, to 

 undertake to transport from Hawaii and establish in the cane fields of 

 Fiji, the Tachinid fly (Ceromasia sphenophori) which is parasitic on 

 the cane beetle borer {[Sphenophorus] Rhabdocnemis ohscurus). 



I had just a month before my boat was to sail in which to make all 

 preliminary arrangements, so I at once began a search of the various 

 plantations on the Island of Oahu that I might collect as large a number 

 of the parasites as possible. It was decided to carry the majority of 

 the parasites in the form of maggots within the borer grubs since the 

 adult flies are very difficult to keep alive in confinement. • Previous 

 investigation had shown that the parasitized grubs must be kept sepa- 

 rate or they will quickly destroy each other. The most practical 

 method, already developed, was the separation of the grubs into in- 

 dividual vials. Although the grubs when thus separated will live for 

 several weeks without food, I decided to keep them well supplied, by 

 placing bits of fresh cane in the vials from time to time as fast as they 

 ate it. In this way I hoped to favor the development of the parasites. 

 When the grubs were left in empty vials for some time, they were found 

 to gradually decrease in size, and the resulting parasites were poorly 

 developed. 



During the collection of parasitized grubs many puparia of the flies 

 were found inside the borer cocoons; these were all saved, hoping, that 

 part of them at least would not emerge until I reached Fiji. However^ 

 some of the flies emerged from these daily, but a few lasted through. 



It was with much difficulty that I found a locality in the vicinity 

 of Honolulu that would furnish sufficient parasites for my needs. The 

 evidences of the flies were everywhere, but they had done their work 

 and gone. Empty puparia were found in most of the borer cocoons. 

 Even in a small field of the Honolulu Plantation, which had been aban- 

 doned because of the abundance of borers, I found few grubs. Almost 

 every stalk had been infested, but the empty puparia were all that 

 remained to show that the flies had been there and done their work. 



By much traveling from one end of the Island to the other I was 

 able to collect, with assistants, about 1,000 of the borer grubs. I 

 had to take a chance that most of them would be parasitized, since 



^ Contribution from The College of Hawaii. 



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