222 MY STUDIO NEIGHBORS 



question for a moment that had the flower been 

 visited in its twilight or moonlight haunt the 

 murmur of humming wings about the blossom's 

 throat would have attested the presence of the 

 flower's affinity, for without the kiss of this identi- 

 cal moth the Angraecum must become extinct. 

 No other moth can fulfil the conditions necessary 

 to its perpetuation. The floral adaptation is 

 such that the moth must force its large head far 

 into the opening of the blossom in order to reach 

 the sweets in the long nectary. In so doing 

 the pollen becomes attached to the base of the 

 tongue, and is withdrawn as the insect leaves the 

 flower, and is thrust against the stigma in the 

 next blossom visited. This was clearly demon- 

 strated by Darwin in specimens sent to him, by 

 means of a probe of the presumable length and 

 diameter of the moth's tongue. Shorter-tongued 

 moths would fail to remove the pollen, and also to 

 reach the nectar, and would thus soon learn to 

 realize that they were not welcome. 



The Angrjecum also affords in this long pen- 

 dent nectary a most lucid illustration of the pres- 

 ent workings of natural selection. The normal 

 length of that nectary should be about eleven 

 inches, but in fact this length varies considerably 

 in the flowers of different plants, this tendency to 



