More than thirty years ago I was introduced to you at your rooms in Christ's College by A.W. Grisebach, and had the pleasure of seeing your noble collection of British Coleoptera. Some years afterwards I became a Fellow of Trinity, and finally gave up my Fellowship rather than go into Orders, and came to this country. For the last five or six years I have been paying considerable attention to the insect fauna of the U.S., some of the fruits of which you will see in the enclosed pamphlets. Allow me to take this opportunity of thanking you for the publication of your "Origin of Species," which I read three years ago by the advice of a botanical friend, though I had a strong prejudice against what I supposed then to be your views. The first perusal staggered me, the second convinced me, and the oftener I read it the more convinced I am of the general soundness of your theory. As you have called upon naturalists that believe in your views to give public testimony of their convictions, I have directed your attention on the outside of one or two of my pamphlets to the particular passages in which [I] have done so. You will please accept these papers from me in token of my respect and admiration. As you may see from the latest of these papers, I [have] recently made the remarkable discover that there [are the] so-called "three sexes" not only in social insects but [also in the] strictly solitary genus Cynips. When is your great work to make its appearance? [I should be] much pleased to receive a few lines from you. LETTER 177. TO B.D. WALSH. Down, October 21st [1864]. Ill-health has prevented me from sooner thanking you for your very kind letter and several memoirs.