78 THE AMERICAN MONTHLY [March 



agents of fertilisation that the plants lay themselves out 

 to produce conspicuously-brilliant or sweetly-smelling 

 flowers indicative of the honey which the insects will find 

 there. In some few cases, however, the plants do 

 not merely attract the passing insects, but they will 

 give them temporary lodging, allowing indeed the eggs 

 to hatch and the lavsB to develop within their ovary. 

 These instances we must look upon as temporary sym- 

 biosis. 



This is the case in the barren fig (Caprificus), in which 

 a species of wasp habitually lays its eggs in the ovaries 

 of the female flowers, which are situated at the base of 

 a flask-shaped receptacle. In these infected ovaries the 

 eggs are hatched, and the larvje feed on the developing 

 ovules, which, however, are killed by them. When the 

 insect is fully developed and has attained the wing- 

 bearing stage, it leaves the flask-shaped receptacle, but 

 not without carrying away some pollen from the male 

 flowers, which are situated near the mouth of the flask, 

 and with which they fertilise the flowers of the next. 

 So for the sake of some ovaries bearing fruit the others 

 are sacrificed, and the mutual benefit satisfies the part- 

 ners. 



In the edible fig no such breeding of wasps can take 

 place, as the ovaries are better protected, and resist 

 the attacks of the mother wasp. How then are their 

 flowers fertilized? They cannot fertilize themselves, 

 for the male and female flowers ripen at difi"erent 

 times. Formerly it was thought that some mysterious 

 influence passed from the barren fig to the edible fig, and 

 hence branches of the former were hung up on the ordin- 

 ary fig trees, an act which was termed caprification. 



Now, however, we know that this mysterious influence 

 is none other than the passage of wasps from the barren 

 fig carrying pollen to the edible fig with intent to lay 



