CAPRIFICATION OF THE FIG. 119 
the Blastophaga was not required, but that any insect would do the 
work. In order to carry the pollen from one fig to another it is by no 
means necessary that the insect should breed in the fig. All it has 
to do is to crawl into the caprifig at the proper time and then crawl 
out and into the edible fig, and the pollination is accomplished; 
but in order that any practical result to the crop at large may come 
from this visit, several circumstances are imperatively necessary, and 
must coincide. The insects must make these visits at the proper 
time; they must be of proper size to be able to enter the closed eye 
of the fig; they must be present in sufficiently large number to pol- 
linate the fig crop, not single figs. As to the first point it will be 
seen that no other insect has been found which will have any busi- 
ness in the eaprifig at the time when required; and even if the pollen 
of the caprifig would serve as its food, it would have no cause to 
afterwards visit the edible fig, which at the period when such visit is 
required does not produce any food, it being green and hard, with no 
trace of sugar. Insects only visit flowers in search of food or to lay 
their eggs. No other insect than the Blastophaga has been found to 
do the latter properly and at the time when required. The second 
point is readily understood. The eye of the edible fig is closed, and 
only an insect with a peculiarly developed instinct would know how 
to push its way between the closed scales. At this stage of the 
development of the fig no insects have been found which visit the 
figs, except the Blastophaga and some parasitical wasps which prey 
on her brood, and which would not enter the fig unless they knew 
the Blastophagas were already there. The most important point, 
however, is the quantity of insects required at a given time. Only 
an insect which will actually breed in the eaprifig can be depended 
on, and it must breed in countless numbers. A few visitors would 
have no practical influence on the fig crops. They may fertilize or 
pollinate a few flowers, but they would be of no practical value to the 
grower and would not produce acrop. Taking it all in all no insect 
has been known, and no one is likely to.ever be known, that can be 
substituted for the Blastophaga grossorum. 
DIFFERENT SPECIES OF BLASTOPHAGA IN DIFFERENT SPECIES OF FIGS. 
As far as is known, different species of figs are, as a rule, inhabited 
by distinct and characteristic species of inquilines. Thus blasto- 
phage grossorum has been found in only one or two nearly related 
fig species, and no other Blastophaga species has been found in our 
eaprifigs. Parasitical wasps are always found together with the Blas- 
tophagas, preying on and developing in them just as the Blastophaga 
preys on and develops in the embryo of the fig. Even when differ- 
ent fig species grow close together do the wasps keep to their respec- 
tive fig hosts; accidentally the wasps may visit other figs, but they 
do not breed in them. It appears almost certain that every fig 
23740—No. 9—O1 
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