a 
25 
17. Reference to Bourdillon’s original paper, however, showed 
that this had been considerably misquoted by Knuth, as Bourdillon 
referred specially to bees and mentioned Lepidoptera only as subsi- 
diary agents in pollination. The following is a copy of the original 
letter (“ Nature” XXVI, 580; 20th October 1887) :— 
“ T send you the following notes on the fertilization of the coffee 
plant (C. arabica) which I made sometime ago, and which may be 
interesting to those who study the subiect. 
“ Your readers are doubtless aware that coffee was cultivated 
some twelve years ago to avery large extent in Ceylon and South 
India, but owing to the attacks of leaf disease, the area has been 
rapidly reduced, except, I believe, in some parts of Coorg and Mysore, 
where the climate is drier, and the leaves suffer less from the fungus. 
It has now been largely replaced by tea. 
‘The jasmine-like flowers of the coffee are borne in clusters in 
the axils of the leaves, and appear simultaneously all over the estates. 
After a prolonged drought of one or two months, or even more, at 
the beginning of the year, there is generally a heavy fall of rain, 
sometimes lasting only an hour or two, sometimes continuing for two or 
three days: the amount that falls must be enough to saturate the 
ground, and should not be less than one inch. 
“ In from six to eight days from the time of the first shower, the 
flowers burst into full blossom, last for a day, and then drop off. On 
the evening before the blossom is fully out, if the flowers are examined 
it will be found that they are partially open, the stigma being pro- 
truded and receptive. During the night the hum of insects can be 
distinctly heard, and I am of opinion that the flowers are largely 
fertilized by night-flying insects which carry pollen from those 
flowers which happen to be open rather before the others, as some 
are delayed. On the following morning all the flowers will be found 
open, and the field of coffee presents a sheet of white. These flowers 
are frequented by immense numbers of bees, of two kinds, one about 
three-quarters of an inch long and black, the other smaller and with 
white bands round its abdomen. The stigmas now are covered with 
pollen, and the anthers bursting, and the larger of these bees may be 
seen buzzing from flower to flower sweeping up the grains of pollen 
between its front legs, and rolling them, into balls. Long before 
evening all the anthers are exhausted of pollen, and the insects have 
departed. Besides bees, some butterflies visit coffee, such as Hypolim- 
nas bolina, Papilio polymnestis, and two or three Danaide. 
“The coffee plant by being proterogynous is intended by nature 
to be cross-fertilized but owing to all the plants in one clearing being 
usually grown from seed of a single estate, there must be a great deal 
of interbreeding, more especially as all the coffee of Ceylon and most 
of South India is supposed to be descended from a single plant 
introduced into Batavia about two centuries ago. This may have 
something to do with the manifest deterioration in stamina of the 
younger coffee. 
Quiton, S. TravancorE, Inpra, T. F. Bourpinton.” 
18th September 1887. 
