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Darwin Correspondence Project

From Thomas Belt   28 July 1874

Cornwall House   Ealing

July 28th 1874

My Dear Sir,

I send you the following as it may possibly add something to your facts about bees. The pole beans (P. multiflorus)1 in my garden have been today visited by some Humble bees which instead of getting at the nectar in the regular way have bored holes through the base of the flowers— I did not notice them doing this until this afternoon and they cannot have been practising it more than a day or two at the most. I know this is nothing unusual and was recorded by you many years ago—2 But the remarkable fact is that the Hive bees which are very numerous were until today getting at the nectar with difficulty by the regular channel but the whole of them this afternoon have discovered the holes made by the humble bees and although not one half the flowers have yet been perforated by the humble bees the hive bees are entirely neglecting the perfect flowers and are spending the whole of their time looking for the flowers that have been perforated at the base by the humble bees—

Of the latter more than one half probably about two thirds are visiting the flowers in the regular way but if the practice spreads and becomes general most of the flowers by & bye will be I should think sterile. I learn from a friend that some pole beans grown in the City where no bees frequent them are invariably sterile

I ought to have said that the humble bees that are making the holes at the base of the flowers are doing so to every flower they visit— If this habit were to become general the cultivation of the pole bean might be rendered unprofitable but I expect there is some check to the practice spreading—3

I hope you are enjoying better health than when I last heard from you

I am Dear Sir | Yours very truly | Thomas Belt

CD annotations

1.7 But the … afternoon 1.9] double scored red crayon
1.10 the hive bees … the flowers 1.12] scored red crayon; scored blue crayon
2.1 Of … general 2.2] scored ink
Top of letter: ‘Habits of Bees’ ink
End of letter: ‘Perhaps I cd. work in T. H. Farrer on Coronella; but in this case it is probable that Bees probiscis accidentally touches nectar on outside of calyx.—’4 ink


Phaseolus multiflorus is a synonym of P. coccineus, the scarlet runner-bean.
CD had written about humble-bees (now more commonly known as bumble-bees) making holes in the flowers of garden beans in a letter to Gardeners’ Chronicle, [16 August 1841] (Correspondence vol. 2).
In Cross and self fertilisation, p. 151 n., CD mentioned a published account by Belt (in Belt 1874) of a crop of Phaseolus multiflorus rendered barren by the activity of humble-bees.
Thomas Henry Farrer had recently published the results of his investigations into the floral morphology of the genus Coronilla and the bees that visited the flowers (Farrer 1874). Farrer had described nectar excreted outside the calyx in some species.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Farrer, Thomas Henry. 1874. Fertilisation of papilionaceous flowers—Coronilla. Nature, 2 July 1874, pp. 169–70.


Has observed in his garden hive-bees using the holes bored at the base of flowers by humble-bees.

Letter details

Letter no.
Thomas Belt
Charles Robert Darwin
Sent from
Source of text
DAR 46.2: C58–9
Physical description
3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9572,” accessed on 29 September 2020,

Also published in The Correspondence of Charles Darwin, vol. 22