28o THE WONDER OF LIFE 



is therefore of little or no use in pollination. The other 

 species of humble-bees enter by the mouth of the flowers, 

 and it is their visits that really count. Mr. Thomas Belt 

 made the interesting observation that in the beginning of 

 the season some individuals of Bombus terrestris visit the 

 flowers of the scarlet-runner in a legitimate manner, but 

 soon discover that there is a shorter way by biting a hole. 

 They burgle unopened buds in the same way, and the 

 hive-bee has learned to utihze the humble-bee's perfora- 

 tions. Large gaping flowers such as those of Foxglove 

 and Nasturtium are pollinated by Bombus terrestris, but 

 the narrower ones are cut through and despoiled without 

 benefit. 



The Case of the Fig. — Of all the mutual relationships 

 that are involved in pollination, those concerned with the 

 fig are perhaps the most remarkable. The whole story 

 has not yet been cleared up, and it is too complex for full 

 discussion here. Utilizing a luminous article by Prof. F. 

 Cavers, we shall simply seek to explain the intricate part 

 which certain minute wasps play in the fertihzation. As 

 is well known, the flowers of the fig are formed within a 

 hollow, pear-shaped receptacle with a narrow mouth. Just 

 below the mouth are the male flowers ; the rest of the cavity 

 is lined by the female flowers ; all are very minute. Early 

 in Spring a female wasp (usually Blastofhaga grossorum) 

 enters the cup of the early inedible inflorescences of the 

 wild fig before the male flowers are open, and lays her eggs 

 in the female flowers. These eggs hatch into wingless 

 males who never escape and winged females who fly away 

 after they have been fertiUzed by the males. As they creep 

 out they get dusted with poUen from the male flowers 

 which have meantime opened. They visit a later crop of 



