the prototype of V. Urticae ? 7
something more nearly allied to V. C-album; and some of the
species allied to the latter are very dark indeed.
"Lastly, as about half the species in the genus have the
wings far more deeply dentated and subcaudate than the
other half, whilst many gradations between the extremes of
these two types exist, it seems most natural to look for the
progenitor in a species which exhibits variation of form
in accordance with the season, so that one may account for
the prevalence of one type in one climate and of the other in
another; and to regard two species of the same type as
descended one from the other, especially when these two
co-exist throughout Europe (or nearly so), seems to me to be
a supposition in the highest degree improbable."]