VII CREATION BY LAW 147 
inches, and was chiefly fertilised by a species of moth which 
appeared at the time of the plant’s flowering, and whose pro- 
boscis was of the same length. Among the millions of flowers 
of the Angraecum produced every year, some would always be 
shorter than the average, some longer. The former, owing 
to the structure of the flower, would not get fertilised, be- 
cause the moths could get all the nectar without forcing their 
trunks down to the very base. The latter would be well 
fertilised, and the longest would on the average be the best 
fertilised of all. By this process alone the average length 
of the nectary would annually increase, because, the short- 
nectaried flowers being sterile and the long ones having 
abundant offspring, exactly the same effect would be produced 
as if a gardener destroyed the short ones and sowed the seed 
of the long ones only; and this we know by experience 
would produce a regular increase of length, since it is this 
very process which has increased the size and changed the 
form of our cultivated fruits and flowers. 
But this would lead in time to such an increased length 
of the nectary that many of the moths could only just reach 
the surface of the nectar, and only the few with exceptionally 
long trunks be able to suck up a considerable portion. 
This would cause many moths to neglect these flowers 
because they could not get a satisfying supply of nectar, and 
if these were the only moths in the country the flowers would 
undoubtedly suffer, and the further growth of the nectary be 
checked by exactly the same process which had led to its 
increase. But there are an immense variety of moths, of 
various lengths of proboscis, and as the nectary became longer, 
other and larger species would become the fertilisers, and 
would carry on the process till the largest moths became the 
sole agents. Now, if not before, the moth would also be 
affected, for those with the longest probosces would get most 
food, would be the strongest and most vigorous, would visit 
and fertilise the greatest number of flowers, and would leave 
the largest number of descendants. The flowers most com- 
pletely fertilised by these moths being those which had the 
longest nectaries, there would in each generation be on the 
average an increase in the length of the nectaries, and also 
an average increase in the length of the probosces of the 
