Dear D^r. Darwin

In consequence of the sad loss which the Museum has recently sustained in the death of our Assistant Keeper, M^r. Frederick Smith, the post of Assistant Keeper in the Zoological Dept. has now become vacant.¹

As next in position, I naturally look forward to being permitted to occupy this office, but as it will be necessary for me to secure the support of leading Men of Science, and am sure that you are aware of my zeal in the acquirement and dissemination of Biological Science, I write to ask you kindly to give me a testimonial.

My scientific papers, as you are aware, treat of almost all Orders of Insects, of Arachnida & Myriopoda; many of them are Monographs or Revisions of Families and Genera: my principal papers on Arachnida are specially referred to in M^r. Cambridge’s Article on the Arachnida in the present ed. of the Encyclopædia Brittanica.²

I have now been in the Zoological Dept. since 1863, and my studies in the various Orders under my charge have, as my present position testifies, given satisfaction to my Superior Officers.

At one time I commenced the arrangement & study of the Crustacea, but was unable to devote sufficient time to them to do them justice. I have also, from my long stay in the Dept. had some insight into other groups of Animals.

In D^r. Gray’s time, I had a certain amount of insight into the working of the Department and therefore have every reason to believe that I should be able to discharge the duties of the office with satisfaction to my chief.³

Believe me to be | Very sincerely yours | Arthur G Butler

D^r. Ch. Darwin F.R.S. | &c &c &c