[16]

It is a doubtful point whether masculine characteristics first appear exclusively in male & are transmitted exclusively to the male, or whether they are first transmitted equally to both sexes & excluded from female through selection. I originally leaned to former view. Mr Wallace apparently rather to latter & has proved it to larger extent – Rudiment in female wd seem the indicate same view, but might originate from some of the successive variations being transmitted to both sexes. Both views probably are true

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[16v]

to certain extent - Crimson head in Picus major & minor, in males alone - probably many cases. Slight difference in smaller &c &c - Slight differences selected in males alone & generally transmitted to males alone. Mr Trimen believes much in Wallaces view in regard to Butterflies & has shewn preponderance of males. But other causes for this preponderance, for Mr Trimen tells me that at Cape a Butterfly the Zorites, the males do not differ from females yet males wonderfully preponderant & so in some other cases.