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- 



„sects 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 Kemer 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 pecuU- 

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



That this hybridization of Linneons is by no means 

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



