PARASITISM OF MEDITERRANEAN FRUIT FLY IN HAWAII 9: 
The coffee berry is another fruit having a very thin pulp and large 
seed. It is very seldom that 7. giffardianus is reared from maggots 
in this fruit, but the parasitism by the opiine parasites is very high. 
The 11.1 per cent parasitism in October, 1924, shown in footnote 1 of 
Table 3, was the work of the melon fly parasite Opius fletchert Silvestri. 
This parasite is occasionally reared from maggots of the Mediter-. 
ranean fruit fly, but the high parasitism recorded during the month 
mentioned is very unusual. It was probably due to the fact that all 
of the coffee containing the maggots from which it was reared were 
collected in the Kona coffee fields on the island of Hawai. Around 
these fields the Chinese cucumber Momordica sp. grows wild and is- 
very abundant. The fruits of this plant are attacked freely by the- 
melon fly, Bactrocera cucurbitae Coq., the maggots of which in turn 
are highly parasitized, resulting in an abundance of O. fletcheri about 
the coffee fields. 
The mango is an example of a fleshy fruit with a comparatively 
tough skin which does not break easily when the fruit falls. The per-. 
centage of parasitism in this fruit by either the opiine parasites or the. 
chaleid 7. miffardianus is not high. vate 
The guava, which is very abundant about Honolulu, has a very 
thin skin and a deep pulp. The majority of maggots are beyond the 
reach of opiine parasites, and this results in a very low degree of para-. 
sitism by them. The thin tender skin of this fruit breaks easily when 
the fruit falls to the ground or is often punctured by birds or by 
coming in contact with some part of the tree. Consequently, 7. gif-- 
fardianus is afforded an unusual opportunity to enter this fruit, and 
the parasitism by this species is in almost every instance higher than. 
that by any of the opiine parasites. In a number of instances it was. 
higher than the combined parasitism of all three species of opiines. 
These are mentioned as examples of the influence exerted by the. 
structure of the infested fruits upon the effectiveness of the fruit-fly 
parasites, and this influence can be observed by reviewing the records 
in the table of the parasitism in other fruits. 
Table 3 shows that all four species of parasites will attack their host 
in most of the fruits under observation. ‘Though the structure of the 
infested fruit controls to a large extent the parasitism by D. fullawayi, 
the degree of its effectiveness in some fruits can not be attributed to 
this cause. This parasite in the majority of host fruits is compara- 
tively ineffective, whereas in coffee and yellow oleander its effective-. 
ness is greater than that of either of the other two opiine parasites. 
This may be an indication of some preference on the part of this 
parasite for maggots in certain fruits. 
Table 4 records the effectiveness of each species of parasite in all 
fruits collected during each month of the three years. O. humilis was 
first in effectiveness during three months in 1922, during no month in 
1923, and during five months in 1924. Diachasma tryont was the 
most effective during seven months in each of the years 1922 and 1923, 
and during five months in 1924. D. fullawayi was the most effective 
during only one month of the 3-year period under consideration, 
namely, in December, 1924. JT’. giffardianus was the most effective 
parasite during two months in 1922, five months in 1923, and one- 
month in 1924. 
