# From C. O. Waterhouse    19 February 1868

Brit. Mus.

Feb. 19th. 1868.

My dear Sir,

I am very sorry for the delay there has been in answering your letter but it was almost unavoidable.1 I do not know Mr. Murray’s paper on cave insects unless it be the same with the one I mentioned “On insect-vision & blind insects” (Edinb. New Philosoph. Journal. ser. 2. 1857. T. 6. p. 120 &c. fig.)2

This paper contains a list of all the cave insects. The Coleoptera are,

5 Anophthalmus (The species that I have seen are bright

polished, (somewhat pale) testaceous.)

3 Adelops3 (these are covered with fine golden pubescens which

makes them look less shining than the Anophthalmi, they are

testaceous-brown.)

1. Glyptomerus (described as being “rufo-brunneus, nitidus,

abdomine apice femoribus tibiisque posteriorbus

picescentibus”)4

1. Troglorhynchus5 (I have not yet seen a description of this)

3. Leptodirus (We do not possess this genus.)

The Brentus (or rather Taphroderes, Schönh.,) varies in length from $\frac{4}{12}$ to $\frac{7}{12}$ of an inch in the ♂—and from $\frac{9}{24}$ to $\frac{12}{24}$ of an inch in the ♀— The ♂ being small is quite exceptional—nearly all the ♂ are larger than the ♀.6

The species of the genus Taphroderes belonging to the 1st. section (four species from S. America) do not present anything particular in form of mandible.7

I believe the thoracic horns in the Lamellicorns are used in escaping from beneath the ground or from the heart of trees (as the case may be) after the metamorphoses have been undergone.8

Since I wrote last I have seen the blind beetles Leptomastax said to be found “on the sands of the Bay of Beikos”— This is pale testaceous, very bright & polished.

Also Langelandia— I do not know the habits of this— It is an exception to the general rule in being dull & coarsely punctured & fuscous. Murray says “found underground”—9

I forgot in my last letter to answer your question about Brentus— It does belong to the first group of Curculionidæ.10

Hoping you will understand this disjointed rambling, | Believe me, | Yours very sincerely, | Chas. O. Waterhouse.

Chas. Darwin Esqre.

## CD annotations

3.1 The Brentus] ‘Look at specimen’ added pencil
3.1 $\frac{4}{12}$] ‘3$\frac{1}{2}$added ink
3.2 The ♂ … ♀. 3.3] scored red crayon and ink; ‘It is one male alone which is so small.—’ ink
3.3 nearly all the ♂] ‘of this species???’ added ink; ‘or Family?’ added pencil del ink
3.3 larger] double underl ink
5.1 I believe … undergone. 5.3] scored red crayon; ‘As Horns not worn this may be rejected.’ added ink | ‘What evidence | How are Males & females in general size? | I thought eggs deposited separately in pellets.’ added pencil
Top of letter: ‘Londonblue crayon | ‘Keep | The whole passage about Taphroderes may be rejected, or kept as mere curiosity’ ink circled ink

## Footnotes

CD’s letter to Waterhouse has not been found.
In his letter of 12 February 1868, Waterhouse had listed the blind insects described in a paper by Andrew Murray (Murray 1857). CD had evidently asked for more information about coloration in these species.
Adelops is now Ptomaphagus.
Glyptomerus is now a subgenus of Lathrobium (family Staphylinidae). The Latin description may be translated as: ‘red-brown, shiny, with pointed abdomen, rear thighs and shins becoming pitch black’.
Troglorhynchus is now a subgenus of Otiorhynchus in the family Curculionidae.
CD had enquired about the size of the male Brentus; see his annotation to the letter from C. O. Waterhouse, 12 February 1868. Waterhouse refers to the genus Taphroderes as described in Schoenherr 1833–45, 5: 573–5.
Waterhouse alludes to the classification of Taphroderes in Schoenherr 1833–45, 5: 573. In Descent 1: 344, CD described Taphroderes distortus as a ‘curious case’ in which the left mandible of the male was much enlarged.
See CD’s annotation to the letter from C. O. Waterhouse, 12 February 1868.
On Leptomastax and Langelandia, see Murray 1857, p. 130.
Brentus is in the family Brentidae. Brentidae and Curculionidae are now placed in the superfamily Curculionoidea.

## Bibliography

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Murray, Andrew. 1857. On insect-vision and blind insects. Edinburgh New Philosophical Journal n.s. 6: 120–38.

Schoenherr, Carl Johann. 1833–45. Genera et species Curculionidum, cum synonymia hujus familiae. 8 vols. Paris: Roret. Leipzig: Fred. Fleischer.

## Summary

Coloration of blind beetles.

Sizes of sexes in Taphroderes.

## Letter details

Letter no.
DCP-LETT-5897
From
Charles Owen Waterhouse
To
Charles Robert Darwin
Sent from
British Museum
Source of text
DAR 82: A76–7
Physical description
4pp †

## Please cite as

Darwin Correspondence Project, “Letter no. 5897,” accessed on 23 September 2021, https://www.darwinproject.ac.uk/letter/DCP-LETT-5897.xml

Also published in The Correspondence of Charles Darwin, vol. 16

letter