From:
Charles Robert Darwin
To:
Benjamin Dann Walsh
Date:
31 Oct 1868
Source of text:
Field Museum of Natural History, Chicago (Walsh 16)
Summary:
Thanks BDW for extracts about "drumming" [of male Cicada to attract females].
Asa Gray and Hooker doubt that 13–year and 17–year Cicada forms should be considered distinct species. CD is inclined to agree with them.
Suggests observations be made of ratio of females to males in the rarer form.
Contributor:
Darwin Correspondence Project