932 AN INTRODUCTION TO ENTOMOLOGY 



by a single species, Blastophaga psenes, which was introduced into 

 California in order to make possible the production of the Smyrna 

 fig in that state. 



The fruit of the fig-tree consists of a hollow receptacle on the 

 lining of which the flowers are borne. At the apex of the fig there is 

 a more or less distinct opening leading into the interior; it is through 

 this opening that the female fig-insect leaves the fig in which she was 

 developed and enters a young fig in order to oviposit. 



The eggs are laid at the base of a modified form of pistillate flowers, 

 known as gall-flowers, that are found in wild figs; and the larvae 

 produce little galls in which they develop. The female fig-insect when 

 leaving the fig in which she was developed becomes covered with 

 pollen which is thus carried into the young fig which she enters to 

 oviposit, and thus the flowers in this fig are fertilized. 



The male fig-insect is wingless. It crawls about over the galls in 

 the fig in which it was developed and when it finds a gall containing 

 a female it gnaws a hole in it and then thrusting the tip of its abdomen 

 through the puncture fertilizes the female. 



It is only in the wild figs that the gall-flowers are developed; for 

 this reason only the wild figs are suitable for the development of the 

 fig-insects; but the female fig-insects will enter the cultivated figs 

 seeking a place to oviposit and will thus fertilize them. 



Although the numerous varieties of common, cultivated figs do 

 not require the stimulus of pollination and the resulting fertilization 

 of the ovary to make the fruit set, in the case of the Smyrna fig, 

 which is the most desirable variety grown, without this stimulation 

 the young figs soon turn yellow and drop. It is the oily kernel of the 

 fertile seed that gives the Smyrna figs their superior quality. 



The fertilization of the edible figs is termed caprification ; and it 

 is brought about by placing in the fig-trees fruit of the wild figs con- 

 taining the fig-insects. In order, therefore, to produce the Smyrna 

 figs it is necessary to grow also the wild figs, or caprifigs as they are 

 termed. 



There are many species of fig-insects living in the wild figs of 

 tropical and semi-tropical countries. 



SUPERFAMILY EVANIOIDEA 



Family EVANIID^ 



The Ensign-flies 



The family Evaniidae is so distinctly separated from all other 

 families of the Hymenoptera that it is regarded as constituting a 

 separate superfamily. We have in this case a superfamily represented 

 by a single family. 



The family Evaniidas differs from all of the preceding families in 

 the presence of a well-marked anal lobe in the hmdwmgs (Fig. 1170) 

 and it differs from all of the following families in that the petiole of 



