Dec, '12] SEVERIN AND HARTUNG: MEDITERRANEAN FRUIT FLY 445 



the eggs from the oviductus communis were fertilized, another method 

 of attacking the problem was started. 



Hundreds of Mediterranean fruit flies were captured in the field 

 while they were laying their eggs in oranges, and these were placed 

 in captivity in jars and fed on dilute molasses daubed on the sides of 

 the jars. A few days later the females, now overloaded with eggs, 

 were observed ovipositing on the sides of the jar. These eggs were 

 introduced into different parts of green Chinese bananaS; some of 

 them being inserted within the peel, others within the pulp. Again 

 as a check, California oranges were used. None of the eggs developed 

 in either the bananas or oranges. The fact that the eggs did not 

 develop in the oranges and bananas may have been due, it was thought, 

 to the absence of the secretion which the female flies pour over the 

 eggs or to a bacterial or fungus groAvth which always appeared, sooner 

 or later, in the region of the fruit where the eggs were planted. 



To obtain eggs over which the secretion had been poured by the 

 female fruit flies, tropical almonds (umbrella tree or "kamani" nuts), 

 which are seriously infested by this pest, were gathered from the trees. 

 The tropical almonds contain weak acids, one of which is probably 

 malic, while the green Chinese bananas contain stronger acids, one of 

 which is tannic. The eggs of the fruit fly were now transferred from 

 the tropical almonds into various parts of green Chinese bananas, 

 some of the eggs being placed within the peel, others directly beneath 

 the peel and still others within the pulp. In some cases the flower 

 scar of the banana was cut out cone-shaped, the eggs were inserted 

 into the pulp, and then the flower scar was placed back into its normal 

 position again. All parts of the banana that had been cut, were sealed 

 with soft paraffine to keep out bacteria and fungus spores. From 352 

 eggs which were placed in different parts of the bananas, only 2 female 

 flies succeeded in completing their entire life cycle; both of these spec- 

 imens developed from the eggs which had been placed within the pulp 

 of the green Chinese bananas. Through the vitelline membrane of 

 one of these eggs, the young maggot, especially the jaws at the anterior 

 pole, could be plainly seen, whereas little or no development was ap- 

 parent in the other egg when it was first introduced. 



In the next experiment 73 eggs were transferred into various parts 

 of Chinese bananas not as green as those used in the previous experi- 

 ment. From these bananas 13 male and 18 female fruit flies emerged. 

 Of the total number of eggs introduced into the peel and pulp of these 

 bananas, 42 per cent gave rise to maggots which were able to com- 

 plete their life cycle. 



An experiment similar to the preceding was now performed with 

 green Brazilian bananas. A total of 215 eggs were planted in these 



