December, ’20] RIXFORD: SYMBIOSIS OF BLASTOPHAGA AND FIGS 461 
and mamme (winter crop) have been applied. The mamme crop forms 
in autumn on the wood of the current season and the Blastophaga 
from the preceding mammoni oviposits in them when they have 
reached the size of filberts. By December these mamme fruits are 
the size of small walnuts and change but little during the winter. The 
insect hibernates in them in the larval condition and will endure a 
temperature of 14° or-15° F. without injury. As the weather becomes 
warm in spring, the insects develop rapidly and are ready to issue in 
April, when the spring (profichi) crop on the same or other capri 
trees is in a receptive condition. This crop grows in clusters on the 
old wood at the extreme ends of the branches and, unlike the mamme, 
which is nearly spherical, is much larger and usually has a pronounced 
neck. It is produced in enormous numbers, many times greater than 
any other crop, a wise provision of nature, as it is the one which is 
most abundantly supplied with pollen and also the one which is exclu¬ 
sively used to pollinate the main Smyrna crop. The late summer 
crop of the capri tree, known as mammoni, unlike the others, pushes 
from the axles of the leaves on the new wood and matures from August 
to the middle of November. This crop serves to carry the Blasto¬ 
phaga through the late summer and fall months. The Blastophaga 
from these mammoni figs oviposit in the winter crop, and thus the 
cycle of the yearly life of the insect is completed. 
The Smyrna Fig Dependence on the Insect 
The Smyrna fig, by far the best variety in cultivation, is more 
exacting than the Adriatic class in the relation between climate and 
fruit production, as its crop of fruit is absolutely dependent on the 
fertilizing insect (Blastophaga psenes), and its culture on a commercial 
scale is therefore confined to regions where the winters are sufficiently 
mild to permit the mamme, or winter insect-bearing crop, to live 
through without injury. Experience shows that if the mamme crop 
is oviposited in, it will endure about the same temperature as the twigs 
of the tree to which they are attached. All caprifigs, if not oviposited 
in, dry up and fall off. The larva of the insect is just as essential to 
make the caprifigs hold on and mature, as is the pollen to make the 
Smyrna fig hold on and mature. 
The parasitic insect of the Ficus carica species, Blastophaga psenes r 
lives but a short time after leaving the harboring receptacle. The: 
female is shining black, has a good pair of wings, and is less than an 
eighth of an inch in length. The male is brownish yellow and is wing¬ 
less. It is doubtful if the insects eat at all. In 24 hours after issuing 
from the caprifig, most of the females are dead, and in 48 hours all 
have succumbed. Most of the males die in the fig, though consider¬ 
able numbers crawl out after the females have left. 
