August, 12] RIXFORD: FIG FRICTIFICATIOX 353 



being so great that the seeds can be readily picked out with a pair of 

 forceps frorri the mass of galls bj' their juiciness and color. 



As further evidence that all the flowers in the mammoni fig are per- 

 fect female flowers, some of the persistent styles were taken from fertile 

 seeds and others from galls containing fully developed Blastophaga 

 in the same fig and placed side by side under the microscope and were 

 found to be identical in cellular structure and in every other respect. 

 The writer is therefore satisfied that the stigmas of the caprifigs are 

 equally as susceptible to pollination as are those of the female figs, 

 and in fact are so pollinated but fail to produce more than a few seeds 

 for the reason given. 



When the Blastophaga enters the caprifig its stamens are in an un- 

 developed condition and will not be ready to shed their pollen until 

 about two months later, that is at the time when the next generation 

 of wasps is ready to issue. It is therefore impossible for a fig to polli- 

 nate itself. Here then is a striking instance of one of nature's methods 

 of preventing self fecundation. 



Life of the Blastophaga. The beneficent insect upon which depends 

 absolutely the whole Smyrna fig industry was sent over to the United 

 States from Northern Africa in 1899 b}' J\Ir. Walter T. Swingle of the 

 Bureau of Plant Industry of the U. S. Department of Agriculture. 

 He succeeded where others had often failed by confining his efforts 

 to the winter generation and by the ingenious device of wrapping each 

 caprifig in tinfoil to prevent evaporation. ]Mr. Swingle is entitled to 

 full credit for his successful efforts, notwithstanding the fact that the 

 Blastophaga was already here, having been accident allj- introduced 

 with fig trees from the South of Europe about 1865, but not known to 

 orchardists until about three years ago, having been as far as known 

 confined to an isolated tree ten miles west of Modesto. 



In April in the warm valleys of California, the wasp which hibernated 

 in the larval form during the previous few months reaches maturity. 

 The male leaves the gall first. He moves about the interior of the 

 fig and finding a gall containing a female, gnaws a hole through the 

 cortex at the base of the style and inserting his long, slim, abdominal 

 projection, fertilizes the female while still in the gall. The female 

 enlarges the opening and sometimes makes another, usually at the 

 base of the style, probably because it is the point of least resistance. 

 In from 22 to 48 hours she comes out, reaching the open air through the 

 cluster of male flowers, the anthers of which at this time have burst 

 and are shedding large quantities of pollen. She is frequently so 

 loaded that she is unable to fly until she divests herself of much of it 

 in the same way that the common house fly cleans itself. After being 

 relieved of part of the load she flies to the nearest fig and if found to her 



