446 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



bananas, 3 to 15 eggs being inserted in each fruit. Forty-eight male 

 and 55 female flies succeeded to complete their life history in this case, 

 i.e., over 47 per cent of the total number of eggs introduced into the 

 bananas gave rise to fruit flies. 



In our previous experiment with the green Chinese bananas it was 

 found that from 352 eggs inserted into these fruits only 2 fruit flies 

 succeeded in completing their entire life history. In order to deter- 

 mine whether the eggs actually hatch and the young maggots die in 

 the acid medium of green Chinese bananas, 100 eggs were placed 

 within the peel of 10 green Chinese bananas. A small piece of the 

 peel was sliced off, the eggs were inserted into the wound and then 

 the thin portion of the peel was placed back in its normal position 

 and covered with soft paraffine. The vitelline membrane of the eggs 

 turned black almost immediately after the eggs were introduced; this 

 was probably the result of the chemical action of the tannic acid. Four 

 days later the paraffine was removed, the small slice of the peel was 

 raised and it was found that 69 eggs had hatched. Not one of these 

 maggots, however, succeeded in completing its life history. 



Half-grown maggots were now placed within the pulp of green 

 Chinese bananas by first removing the flower scar as described in one 

 of the previous experiments. The majority of these maggots died. 



A similar experiment was performed with 20 nearly full grown mag- 

 gots, one maggot being placed in each green Chinese banana. The 

 results were as follows: 



10 maggots bored out of the bananas and pupated. 

 2 maggots bored out of the bananas and died. 

 8 maggots pupated inside of the bananas. 



The fact that 8 maggots pupated inside of the bananas instead of 

 boring out indicated that the acid medium of the banana was unfav- 

 orable for the development of the larvae. The maggots which bored 

 out of the bananas and pupated in the jars were placed in moist sand 

 and later issued as apparently normal flies. 



The second problem which we attempted to solve was: Will the 

 Mediterranean fruit fly in captivity lay its eggs in green, ripe or over- 

 ripe Chinese bananas f 



Again, hundreds of the adults were captured in the field while they 

 were laying their eggs in oranges and these" flies were then confined in 

 jars containing from 6 to 12 green Chinese bananas. Occasional ob- 

 servations showed that the specimens did not deposit their eggs within 

 the bananas, but only on the sides of the jars and the external surface 

 of the bananas. The eggs deposited upon the peel, however, did not 

 develop. 



