HYMEN OPT ERA 355 



reason only the wild figs are suitable for the development of the fig-in- 

 sects; 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 containing 

 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. 



THE COMMON WASPS, ANTS, AND ALLIES 



This is a large group of hymenopterous insects which are closely 

 related in certain details of external structure but which vary consid- 

 erably in habits and appearance. It includes the well-known wasps and 

 hornets, the ants, the velvet-ants, the tiphiid wasps and others, some 

 fourteen families in all, of which only a few can be discussed here. 



Family Pompilid^e 

 The Spider-wasps 



The members of this family are commonly called spider-wasps, be- 

 cause they provision their nests with spiders; this habit, however, is not 

 distinctive as certain other wasps use spiders for this purpose. 



The members of this family are slender in form, with long spiny legs. 

 The pronotum extends back on each side to the tegula; and the abdomen 

 is sessile. Many of the species are of medium size, but some are very 

 large; in fact, the largest of our Hymenoptera belong to this family. 



Most of the Pompilidas make their nests in the ground. The wasp 

 first finds a spider and stings it until it is paralyzed, and then digs a 

 burrow, which is enlarged at the lower end, forming a cell for the recep- 

 tion of the spider; the spider is then dragged down into the cell and an 

 egg attached to it; then the passage leading to the cell is filled with 

 earth. 



Among the giants of this family are the well-known tarantula-hawks 

 of the genus Pepsis of the Southwest, which store their burrows with 

 tarantulas. Many a hard-fought battle do these spider-wasps have with 

 these enormous spiders, and sometimes they are conquered and ignomin- 

 iously eaten. 



Not all members of this family are digger-wasps, for some are mason- 

 wasps. The species of one genus make thimble-shaped cells, of mud, 

 attached to the lower surface of stones, in chinks of walls, under bark and 

 in various other situations. The books, "Wasps Social and Solitary," by 

 the Peckhams, and "Wasp Studies," by theRaus, contain most interesting 

 accounts of these wasps. 



