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April 29 /66/ Sexual Selection affects ordinary characters, Mr Gould shewed me two species of Ring Dotterels, in one of which male & female alike; in the other the ring more complete & top of head ochre-colour. In allied species certain similar feathers are especially modified.

In Humming Birds sexual ornaments are only temporary. He shewed me curious case of a new species in which the female had outer tail-feathers topped with white, as is usual

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with many forms, whilst the male had outer black & tips of central feathers (of which no other case occurs) snow white; so that the white tips in male had travelled from outside to centre of tail, & this clearly sexual. (This case of tail of Humming Birds shows that some change, without any addition of beauty, pleases the female, like change of fashion in dress with us.)