jan. 94,1916 Banana, Host Fruit of Mediterranean Fruit Fly 
799 
removed after 24 hours; 15 fruits after 72 hours. At the end of the 72 
hours, or 7 days after the fruits were cut, they were beginning to turn 
color. In the peel of the 5 fruits first removed 58 punctures were made; 
yet only 1, 3, 2, and 1 fruit flies, respectively, were reared from 4 of the 
fruits. In the peel of the 15 fruits removed at the end of 72 hours there 
were 148 punctures, of which 28 contained eggs. Two days after the 
fruit was removed from the jars, the 28 punctures were found to contain 
59 hatched eggs and 27 dead eggs. While punctures were found to be 
entirely empty in only 2 of the 15 fruits, adult fruit flies failed to mature 
in 7. There issued from the remaining 8 fruits an average of 2.2 flies, 
8 being the largest number to emerge from a single fruit. Two fruits, 
found to contain 18 and 19 eggs, respectively, failed to produce adults. 
Three fruits of the wild Borabora banana, which had been cut from the 
tree for two days and were still hard and yielding small quantities of sap 
when cut from the bunches, were placed with about 200 fruit flies for 24 
hours. After removal from the cage, one fruit contained 56 eggs in its 
peel. The two other fruits were placed in fearing jars and produced 104 
and 187 adult fruit flies, respectively. The pulp of the Borabora banana 
is very firm and does not decay as rapidly as does that of the Chinese or 
Bluefield banana. 
Only 35 adults matured from 880 eggs taken from apples and placed 
in the peel of 44 bananas that had been cut for shipment for 24 hours. 
Of the 44 fruits only 31 produced adult fruit flies. Out of 107 newly 
hatched larvae from apples, placed in the pulp of ripe bananas, but 33 
succeeded in reaching the adult stage. Out of 137 newly hatched larvae 
placed in the pulp of green bananas ready for shipment, but 40 com¬ 
pleted the life cycle. Of these 137 larvae 15, 52, 60, 26, and 10 were 
placed in bananas that had been cut from the tree 1, 2, 3, 4, and 9 days, 
respectively; the adults reared in the same order numbered 3, 12, 13, 
5, and 7 
CAUSES OF IMMUNITY OF GREEN BANANAS TO FRUIT-FLY ATTACK 
While it is difficult to understand why Mediterreanean fruit flies have 
not been reared from ripe and split fruits collected on the plantations, 
it is not so difficult to find reasons for the immunity of fruits until they 
are about to turn yellow. Chemical analysis of the banana during its 
development, made by Mr. A. R. Thompson, of the Hawaii Agricultural 
Experiment Station, have shown that there exists much tannin i n the 
peel and about the sections of which the banana fruit is composed. This 
tannic add is very abundant in the green fruit, but decreases greatly in 
amount as the fruit becomes edible. During development, even up to 
the time when bananas are cut for shipment, which usually is about 12 
to 16 days before they would become ripe enough to eat if kept under 
Hawaiian weather conditions, the peel of the fruit is so surcharged with 
sap laden with tannic add that the slightest scratch of the peel produces 
