Oswald Heer [in Die Urwelt der Schweiz (1866)] agrees with CD that Swiss ants (Formica sanguinea) capture more slaves than do British ants. Does this contradict selection, since the British ants are exposed to harder conditions and a poorer fauna?

Calls for more study of behaviour and less of classification to determine whether descent theory can bear the weight not [only] of reasoning but of fact. Hopes CD’s intended book [Variation] will help.