THE EVOLUTION OF LIVING BEINGS. 125 



such pollen also (in the first place to cover the great 

 loss of such pollen during transportation, they must pro- 

 duce it in very large quantities) crossfertilisation 

 between many Linneons of plants must have been al- 

 most impossible before insects came into existence. 



The birth of insects consequently offered new possi- 

 bilities of crossing and consequently of the birth of new 

 species. 



Darwin clearly perceived this, as results from a letter 

 he wrote to Hooker on Aug. 6th 1881 (Life and Letters 

 III p. 248). 



„Nothing is more extraordinary in the history of the 

 „ vegetable kingdom as it seems to me, than the appa- 

 rently very sudden or abrupt development of the 



„higher plants Hence I was greatly interested by a 



„view which Saporta propounded to me a few years 

 „ago viz, that as soon as flower-frequenting in- 

 jects mere developed, during the latter part of the 

 „secondary period, an enormous impulse was given to 

 „the development of the higher plants by crossfertili- 

 „sation being thus suddenly formed." 



Of course the influence of dichogamy remains the 

 same in favoring crossfertilisation of Linneons whe- 

 ther the wind or insects are the transporters of the 

 pollen, and so it is quite correct that Kerner makes the 

 general statement, that dichogamy favours bi-specific 

 crossing especially at the beginning and at the end of 

 the flowering period of all plants possessing this peculi- 

 arity (cf. 1. c. II p. 315). 



That this hybridization of Linneons is by no means 

 of rare occurrence, Kerner, who was the first to recog- 



