the case of Angraecum sesquipedale, a species from Madagascar, on
observing the 30cm spur in the lip, Charles Darwin theorised that,
since the nectar was at the bottom of the spur, a pollinator must exist
with a tongue at least that long. Otherwise the orchid could never be
pollinated. At the time, he was not believed. However, long after
Darwin's death, the predicted pollinator was discovered, a hawk moth
now named Xanthopan morganii praedicta (praedicta meaning predicted).
It had an appropriately long proboscis. The specific name
'sesquipedale' means 'one foot and a half', referring to the length of
the spur. This is a perfect example of mutual dependence of an orchid
and a specific pollinator".