208 OUR INSECT FRIENDS AND FOES 



immediately devote themselves to laying eggs, 

 and in the process are of necessity brought into 

 contact with the stigmas of female flowers. 

 The wasps are still powdered over with the 

 pollen from their birthplace, and it is now 

 brushed off on to the stigmas, which are 

 thus pollinated from another inflorescence. If 

 the pollen is deposited on normal pistilli- 

 ferous flowers the latter are able to develop 

 seeds endowed with the power of germina- 

 tion ; if it falls on gall-flowers it is, as a 

 rule, ineffectual, because the stigmas are more 

 or less abortive. Moreover, no seeds are formed 

 in these gall-flowers, owing to the eggs of the 

 wasp being laid in their place. In those species 

 of Fig in which gall-flowers are not specially 

 provided, the eggs are laid in a certain proportion 

 of the normally developed female flowers. It 

 has, however, been observed in the case of the 

 common Fig (Ficus Carica) that eggs of Blasto- 

 phaga grossonun laid in ordinary female flowers 

 do not come to maturity, or, in other words, 

 that a normal female flower is not converted into 

 a gall, even if the wasp in question sinks its 

 ovipositor into it and deposits an egg in the 

 interior. For the style of the normal female 

 flower of Ficus Carica is so long relatively to the 

 ovipositor of Blastophaga grossorum that the egg 

 cannot be inserted quite into the ovary, but is 

 left at a spot which is not favourable to its 

 development, and there perishes. The gall- 

 flowers of this species of Fig, with their short 

 styles, are, on the other hand, pre-eminently 

 adapted to the reception of the egg at the spot 



