30 



INSECTS 



There are many others among the Hymenoptera 

 that are useful in the work of polHnation because of 

 their habit of feeding among the flowers, even if not on 

 them ; but all this is based on the same visits which the 

 flower encourages and of which it takes advantage; 

 but no account of this sort 

 of relationship could be con- 

 sidered even passably com- 

 plete, without some reference 

 to the complicated relation- 

 ship existing between the 

 Smyrna fig and the minute 

 little Blastophaga, a species 

 whose life relations have been 

 beautifully worked out by the 

 Entomologists of the United 

 States Department of Agri- 

 culture. 



The Smyrna fig of com- 

 merce depends for its edible 

 quality upon the ripened 

 seeds that it contains. The 

 fig is not really a true fruit 

 as that term is generally 

 defined, but is a thick fleshy 

 envelope within which the 

 flowers are contained. In 

 the Smyrna fig these flowers 

 are all female and no pollen is produced anywhere on 

 the tree. Left to themselves, such trees could never 

 produce ripe fruit, and that was the condition of the 

 Smyrna fig orchards in CaUfornia; prior to 1900. In the 

 Mediterranean countries, whence our commercial sup- 

 ply is generally derived, there are found beside the culti- 

 vated also several varieties of wild or caprifigs, which 



F1G.8.— a, cell of ^MgocWora with 

 egg laid on pollen mass; b, cell of 

 Andrenid with egg resting on mix- 

 ture of pollen and honey; c, cells of 

 carpenter bee in wood; d, mud cells 

 of mason bee in burrow — c and d, 

 after Packard. 



