The Descent of Man

one species both are of a beautiful shining
green, but the male has a red thorax. On the
whole, as far as I could judge, the females of
those Prionidae, in which the sexes differ, are
coloured more richly than the males, and this
does not accord with the common rule in regard
to colour, when acquired through sexual
selection.
[Fig.16. Chalcosoma atlas. Upper figure, male
(reduced); lower figure, female (nat. size).
Fig. 17. Copris isidis.
Fig. 18. Phanaeus faunus.
Fig. 19. Dipelicus cantori.
Fig. 20. Onthophagus rangifer, enlarged.
(In Figs. 17 to 20 the left-hand figures are males.)]
A most remarkable distinction between the
sexes of many beetles is presented by the great