My dear M^r Darwin,

With reference to the protection which the females of the Brimstone Butterfly & Orange Tip derive from their resemblance to White Butterflies—the latter are so ubiquitous that there is no doubt that all occur together—but unless you find that birds refuse to catch the Common white butterflies I am afraid the others would derive no protection from this resemblance, except from young Entomologists, a class I fear hardly sufficiently numerous to produce a sensible effect on the colouring of female butterflies.¹

D^r Wallace’s suggestion with reference to the larvæ of females being collected in preference to those of males from their larger size is no doubt a very good one.—² In the case of the Vapourer Moths—the larger size of the female larvæ must sensibly operate in attracting the eye of the collector & in the Emperor Moth the same thing would operate.³ It was to eliminate this source of error that I appealed to breeders for their experience in breeding whole broods of species.

I have now to thank you for your very kind present of your last new work, which reached me yesterday.⁴

I regret only that the little information I have been able to give you has not been of a more satisfactory nature

Yours very sincerely | H. T— Stainton

C. Darwin Esq