skip to content

Darwin Correspondence Project

From Hermann Müller   16 February 1876


Febr 16, 1876.

My dear Sir

I have been highly interested by your observation on hive and humble bees repeatedly inserting their proboscis between the flowers of Trif. pratense apparently searching for something secreted by the calyx.1 Hitherto I have never made the same observation. As to Bombus terrestris and pratorum ☿, I am absolutely sure that they were acting exactly in the manner described in my work on fertilisation, page 223.2 Concerning hive bees I cannot remember to have seen them boring through the corolla (as I have repeatedly seen with the two mentioned humble bee-species) but I clearly remember to have seen them inserting their proboscis in a hole already bored through the corolla. But of many hundred hive bees which I have seen visiting Trif. pratense for honey I have accurately observed only a small number. Hence I think it very possible that many hive bees may act also here in the manner observed by you.

I have repeatedly observed that different individuals of the same species of Apidae act quite differently in the same species of flowers and in the same locality. For instance last summer in the valley of Sulden near the Ortler I saw some individuals of Bombus mastrucatus Gerst ☿ boring through calyx and corolla of Rhinanthus alectorolophus, other ones (in the same locality) inserting their proboscis between calyx and corolla and boring through the corolla alone.3

In Erica tetralix, in former years, during the summer I saw the hive bees always boring through the corolla and only once (15 Oct, 1871) numerous individuals sucking in the normal way.4 Past year, also: during the summer, I saw many hive bees sucking normally. (Unfortunately I have neglected to examine, whether considerable differences in the length of the corolla are found)

Next summer I will anew watch the visitors of Trif pratense in different localities and measure the length of its corolla. I will be very much obliged to you, if you will send me some specimens of corollae of your Trifolium pratense for comparison.

With very sincere respect | I remain, my dear Sir, | yours faithfully | H. Müller.

P.S. The continuation of my articles in the Bienenzeitung will be retarded for several months by indispensable work for our school-museum.5

CD annotations

2.1 I … locality. 2.2] scored red crayon
3.1 In … way. 3.3] scored red crayon


CD’s letter to Müller has not been found, but CD described the action of hive-bees visiting Trifolium pratense (red clover) in Cross and self fertilisation, p. 361.
In his book Befruchtung der Blumen durch Insekten (Fertilisation of flowers through insect agency; H. Müller 1873, pp. 223–4), Müller had described how Bombus terrestris (buff-tailed bumble-bee) and B. pratorum (early bumble-bee) made holes at the base of the corolla of Trifolium pratense to get nectar, since their proboscises were too short to reach the nectary in the legitimate manner.
The Ortler (Ortles in Italian) is the highest mountain in the Ortles Alps in northern Italy (Columbia gazetteer of the world). Apidae is the family of bees. Bombus mastrucatus (a synonym of B. wurflenii) is an Alpine species of bumble-bee; it has a short proboscis and strong mandibular teeth. Rhinanthus alectorolophus is greater yellow rattle.
In H. Müller 1873, pp. 298–9, Müller described the floral morphology of Erica tetralix (cross-leaved heath) and his observation of Apis mellifera (European honey-bee) visiting the flower.
Müller was writing a series of articles in Bienen-Zeitung under the title ‘Die Bedeutung der Honigbiene für unsere Blumen’ (The importance of honeybees for our flowers; H. Müller 1875–6). The seventh part had appeared in the issue for 31 January 1876; the eighth part appeared on 1 June 1876. Müller taught at the Realschule in Lippstadt (now Ostendorf Gymnasium; Krause 1883).


Columbia gazetteer of the world: The Columbia gazetteer of the world. Edited by Saul B. Cohen. 3 vols. New York: Columbia University Press. 1998.

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

Krause, Ernst. 1883. Prof. Dr. Hermann Müller von Lippstadt. Ein Gedenkblatt. Kosmos 13: 393–401.

Müller, Hermann. 1873. Die Befruchtung der Blumen durch Insekten und die gegenseitigen Anpassungen beider. Ein Beitrag zur Erkenntniss des ursächlichen Zusammenhanges in der organischen Natur. Leipzig: Wilhelm Engelmann.

Müller, Hermann. 1875–6. Die Bedeutung der Honigbiene für unsere Blumen. Bienen-Zeitung: Organ des Vereins der deutschen Bienenwirthe 31 (1875): 81–2, 102–4, 109–11, 122–5, 138–41, 165–9; 32 (1876): 20–2, 119–23, 176–84.


Observations on hive- and humble-bees. Perforating habits differ in different individuals of the same species.

Letter details

Letter no.
Heinrich Ludwig Hermann (Hermann) Müller
Charles Robert Darwin
Sent from
Source of text
DAR 46.2: C61–2
Physical description
3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 10396,” accessed on 27 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 24