The Descent of Man

in number; but three South African species perhaps
offer an exception. Mr. Wallace (78. 'Transactions,
Linnean Society,' vol. xxv. p. 37.) states
that the females of Ornithoptera croesus, in
the Malay archipelago, are more common and
more easily caught than the males; but this is a
rare butterfly. I may here add, that in Hyperythra,
a genus of moths, Guenee says, that
from four to five females are sent in collections
from India for one male.
When this subject of the proportional numbers
of the sexes of insects was brought before the
Entomological Society (79. 'Proceedings, Entomological
Society,' Feb. 17, 1868.), it was generally
admitted that the males of most Lepidoptera,
in the adult or imago state, are caught in
greater numbers than the females: but this fact
was attributed by various observers to the more
retiring habits of the females, and to the males
emerging earlier from the cocoon. This latter
circumstance is well known to occur with most