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Darwin Correspondence Project

From John Ralfs   9 July 1874


July 9th 1874

My dear Sir,

Yesterday I went to the Pingicula Grandiflora bog. I could not go there & to the Utricularia on the same day & as I am rather tired today I think it better to send what I have off today & leave the Utricularia to my next walk. I send, however, a morsel of the latter that I had in a basin merely to show its condition.1

Yesterday I spent a good part of the Day in examining the Pingicula in situ—laying down on the ground so as to enable to use a pocket-magnifying glass without disturbing the plant.

I suppose I must have examined 50 specimens carefully—taking my observations on 3 or 4 plants of one group & then going to another 20, 30 or 50 yards off. The leaves were in excellent condition all with insects in various conditions some in fragments—legs, wings &c. Others dead— some just alive outhers just caught

I noted those on one plant—not too far gone for identification— I cannot tell the exact number as I left the notes at home (I am now writing at the Library). Knats dead— Several flies in various conditions & sizes (Diptera).2 A small species of himipterous Insect (Cicada?)3 both perfect & Larva clear & alive: One I touched on the back with a piece of grass & it made an attempt to jump being retained however by threads as it were of sticky substance   One small moth dead. A small Ichneumon fly— Acari numerous—4 I counted on one leaf 9 dead besides a few still alive— I touched some gently with the grass but they were unable to move away— All the above on one plant—but the result was the same on others except the Insects varied. I noticed here & there a very minute Beetle


& also one small Rove-beetle.5 Still some insects seem to touch it with impunity   In a piece of Rag at top of box—I send a leaf with the larva of a small Moth which eats the cellular tissue of the leaf & finally enters into the pupa state between the two layers of cuticle.6

I did not notice any thing particular with regard to fragments of plants.

So also of seeds— I sometimes found their own seeds on the leaf, a specimen of which I enclose in this letter, and also here & there fruit of Carex pulicaris7 but I could see no alteration when compared with ripe seed I gathered.

I tried to learn something about the P. lusitanica—but it is very difficult to observe them— the leaves are usually entirely concealed by other plants so that the Pingicula is only detected by the flowers8

I am glad my last sending revived so as to enable you to study their action.9

I need hardly say that a Copy of your intended work will be acceptable but believe me—I do not require one for any help I can render you.10 The mere fact of helping you, however little that may be, will afford to me an ample reward.

I remain My dear Sir | Yours truly | John Ralfs

Charles Darwin Esq

CD annotations

1.1 Yesterday … condition. 1.4] crossed blue crayon
3.3 all with … fragments— 3.4] underl red crayon
4.3 (Diptera).] underl red crayon
4.4 himipterous] underl red crayon
4.6 moth] underl red crayon
4.7 9 dead … alive— 4.8] under red crayon
4.10 Beetle] underl red crayon
4.11 Rove-beetle.] underl red crayon
6.2 here & there] underl red crayon
6.2 Carex pulicaris] underl blue crayon
7.1 I tried … reward. 9.3] crossed blue crayon
Top of letter: ‘Pinguicula grandiflora’ blue crayon


In his letter to Ralfs of 8 July 1874, CD had requested specimens of both Pinguicula grandiflora (the large-flowered butterwort) and Utricularia (bladderwort).
Gnats are small insects of the order Diptera, which also includes mosquitoes and true flies.
Cicada is a genus of the order Hemiptera (true bugs).
Ichneumon flies are small parasitic wasps of the order Hymenoptera. Acari is a subclass of the class Arachnida and includes mites and ticks.
The family Staphylinidae (rove beetles) belongs to the order Coleoptera.
The caterpillar of the silver Y moth, Autographa gamma (family Noctuidae) feeds on the leaves of all species of Pinguicula.
Carex pulicaris is flea sedge (family Cyperaceae).
Pinguicula lusitanica is the pale butterwort; see letter to John Ralfs, 8 July 1874, n. 2.


Sends specimens of Pinguicula and observations made on them. [See Insectivorous plants, pp. 390–1.]

Letter details

Letter no.
John Ralfs
Charles Robert Darwin
Sent from
Source of text
DAR 58.1: 73–4
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9540,” accessed on 27 September 2021,

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