Looking at the facts now in the light of more experience it seems to me
just possible that the case may be one in which, as in Nilson-Ehle's
Wheats, the dominant differs from the recessive in having two pairs of
factors with similar effects. The fulvous type for example may have
two or more elements in separate pairs which together produce the full
effect, and the intermediate may have one of these. If this were so,
some segregation should of course eventually be observable, but the
proportion of the various fulvous and fulvous-intermediate individuals
would be large, and the reappearance of actual representatives of the
northern type might be rare. I admit that this is a somewhat strained
interpretation of the facts, and as yet it is not entitled to serious
consideration. Nevertheless I am led to form some such expectation
partly from the great difficulty in the way of any other, partly from
the evidence of the small mixed sample found at Preuilly and partly from
the statements given by Oberthür. There are moreover other features in
the general distribution of the species which make it improbable that
the dependence on climate can after all be so close. Published lists
are unfortunately of little use in deciding which form occurs at a
particular place, because, since the name _Meone_ has ceased to be used
for the southern form, there is no complete unanimity among authors as
to the application of the names _egeria_ and _egerides_, and unless
more particulars are given, either name may be used for either form.
Besides this, difficulty arises from the fact that the intermediate
type is not generally distinguished at all, and English collectors
finding it, may easily record it as the southern type. From Staudinger's
note on the distribution, I gather that he, on the contrary, reckoned
the intermediate with the northern type, as do the Speyers also. The
late Mr. J. W. Tutt was careful to distinguish the three forms and has
left several useful records. Easy therefore as it might seem to be to
make out the distribution of such a familiar insect in its various
modifications, there are serious practical difficulties, and until
long series are brought together with this special object in view many
obscurities will remain.
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