ZiZ CREATION BY LAW. 
by which this is effected, and the Duke of Argyll ad- 
mits the accuracy of his observations. In our British 
species, such as Orchis pyramidalis, it is not necessary 
that there should be any exact adjustment between 
the length of the nectary and that of the proboscis of 
the insect; and thus a number of insects of various 
sizes are found to carry away the pollinia and aid in 
the fertilization. In the Angraecum sesquipedale, how- 
ever, it is necessary that the proboscis should be forced 
into a particular part of the flower, and this would 
only be done by a large moth burying its proboscis 
to the very base, and straining to drain the nectar 
from the bottom of the long tube, in which it occupies 
a depth of one or two inches only. Now let us start 
from the time when the nectary was only half its 
present length or about six inches, and was chiefly 
fertilized by a species of moth which appeared at the 
time of the plant’s flowering, and whose proboscis 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 fertilized, because the moths could get all the 
nectar without forcing their trunks down to the very 
base. The latter would be well fertilized, and the 
longest would on the average be the best fertilized of 
all. By this process alone the average length of the 
nectary would annually increase, because, the short-nec- 
taried flowers being sterile and the long ones having 
abundant offspring, exactly the same effect would be 
