MEDITERRANEAN FRUIT FLY IN HAWAII. 



23 



were reared from the fruits. The flies readily deposited eggs in apples 

 placed with them both before and after exposure of the pineapples. 

 A record of the time each of the 50 fruits was exposed is as follows : 



Table VI. — Nonsusceptibility of pineapples to the attach of the Mediterranean fruit fly . 



Number of 



fruits 

 exposed. 



Dates of exposure to 

 infestation. 



Number of 



fruit flies 



reared. 



2 



1 



1 



2 



6 



10 



12 



16 



1913. 

 Oct. 14-15 



None. 



Oct. 17-18. . . 



Oct. 19-22 



Oct. 23-24 



Oct. 27-29 



Oct. 30-Nov. 2 



Nov. 5-7 



Nov. 9-11 





During July 18-20, 1913, a very ripe pineapple was hung in a jar 

 containing flies. An examination of the fruit after this two-day 

 exposure revealed 2 punctures in the pulp containing respectively 

 16 and 11 eggs. One puncture had been made in a slight abrasion; 

 the other in normal tissue between the eyes. Seven other batches of 

 eggs, containing 9, 5, 8, 7, 4, 5, and 4 eggs, respectively, had been 

 deposited on the surface of the fruit, but in the creases between the 

 eyes. 



In experimental work the writers have had no difficulty in trans- 

 ferring larvae from one favored host fruit to another. Experiments 

 in transferring first, second, and third stage larvae to pineapple 

 invariably resulted in the death of the larva. A total of 925 larvae 

 were transferred, as follows : 



Table VII. — Failure of larvae of the Mediterranean fruit fly to develop in the pulp of ripe 



pineapples. 



Date of transfer. 



Number 



larvae 



transferred. 



Instar when 

 transferred. 



Results. 



Apr. 22. 



150 

 200 

 100 

 25 

 150 

 150 

 150 





All died by Apr. 26. 

 Do. 



Apr. 23 



do 



Apr. 22 



First 



All died by Apr. 24. 



Do... 





19 dead by Apr. 25; 6 dead by Apr. 26. 

 All dead bv Apr. 25. 



Do 



Young third 



Apr. 23 . 



do 



Do. 



Apr. 22... . 



Well grown third 



Do. 







While the experiments above reported indicate that under forced 

 laboratory conditions a few eggs may be deposited within the pulp of 

 very ripe pineapples, the failure of all stages of the larvae to survive 

 in a medium of fresh ripe pineapple pulp is conclusive evidence that 

 the pineapple should be dropped from lists of host fruits of the Med- 

 iterranean fruit fly. 



