My dear Sir,

I hope you will excuse my apparent neglect in not answering your letter sooner when I tell you when I tell you that I have been very unwell the last few days with a severe attack of rheumatic headache which has prevented me from doing many things which ought to have been attended to—¹ it is always a very great pleasure to me to assist you in any way in my power—

In reply to your first question I may say that I have not noticed any marked difference in the numbers of the sexes of Lepidoptera during different years— I have paid pretty close attention to this Order for more than thirty years and my decided opinion is that the males are always more numerous than the females— if this were not the case it does not seem probable that a virgin female would attract fifty or a hundred males in a single day and this I have often witnessed with Saturnia carpini and Bombyx quercus:²

I agree with what D^r Wallace says about collecting larvæ and as those of many species of Macro-Lepidoptera differ very much in size—the females being much larger than the males—they are more conspicuous and consequently are more often collected than the smaller ones which produce males—³ I do not suppose M^r Stainton⁴ has ever reared whole broods of any of the Micro-Lepidoptera from the eggs—it is the only way to ascertain the numbers of each sex—

You may often see five or six males chasing a female butterfly and I certainly think the female is quite indifferent as to which of them copulates with her—and that it is mere chance on the part of the male— I have frequently seen ragged, worn males in copulation with fine fresh females of the common white butterflies—

The females of the large Bombyces such as Carpini and Quercus merely protrude the ovipositor and sit in an almost torpid state—quite motionless—and the first males that gets to them copulate with them immediately— this I have often witnessed— I really think it is all chance and that if a virgin female were deprived of all the scales on her wings and rendered colourless she would be as attractive to the males as a fine and perfect specimen— I give you my candid opinion founded upon observations made through a rather long series of years—

I do not think gaily coloured objects have any particular attraction for butterflies— the common white ones will often fly down to a small piece of white laying on the ground no doubt mistaking it for a butterfly of the same species—⁵

I am pleased that your opinion of Primula elatior accords with my own—⁶

I shall always be most happy to serve you in any way and with best wishes believe me | My dear Sir | Yours very Sincerely | Henry Doubleday

Charles Darwin Esq