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From:
Albert Brydges Farn
To:
Charles Robert Darwin
Date:
18 Nov 1878
Source of text:
DAR 164: 26
Summary:

Discusses colour variations in the geometer moth, Gnophos obscurata. Concludes that the increasing proportion of the darker form is related to the effect of smoke that is blackening the chalk slopes on which they live.

Contributor:
Darwin Correspondence Project
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