butterfly is subject to in this country
is in the size of the orange wing-spots, which are sometimes greatly
enlarged.

In a well-marked variety, common in the south of Europe, Madeira, &c., this
enlargement reaches a great development, nearly the whole of the _upper_
wings being suffused with a deep orange, though in all other respects the
insect does not differ from our common form. This beautiful variety has
been described as a different species under the name of _Gonepteryx
Cleopatra_; but M. Boisduval has proved that they are identical, by rearing
both the ordinary _Rhamni_ and the _Cleopatra_ from the same batch of eggs.

The female _Cleopatra_ does not differ materially from _Rhamni_. I look on
this variety as very interesting, as a probable instance of the direct
effect of increased warmth of climate in intensifying colour.[9]

Plentiful as this butterfly is in all the southern counties, and extending
in more or less abundance as {71} far northwards as the lake district, it
there becomes scarce; and I can find no instance of its having occurred in
Scotland.

Of course, its prevalence in any district is naturally regulated by the
abundance of its food-plants, the buckthorns.

Gardens, fields, and lanes are equally the resort of this favourite insect;
and there the newly-hatched specimens are to be found on the wing from
August to October.

* * * * *

THE CLOUDED YELLOW, OR CLOUDED SAFFRON. (_Colias Edusa._)

(Plate III. fig. 3, Male; 3A, Female.)

This richly-coloured and nimble-winged fly is ever the darling of the
collector. None make a finer show in the cabinet, and few tempt pursuit
more strongly than does this golden beauty when on the wing.

For many years past, and up to quite a recent period, the appearance of
this butterfly in any abundance was a phenomenon only occurring at
uncertain periods, separated by intervals of several years. In one season,
perhaps, hardly a solitary specimen would be seen, and in the very next, a
swarm of them would spread over the southern counties, delighting the
fly-catcher and puzzling the naturalist to find a sufficient reason for
{72} this sudden burst of insect-life. Whether the eggs lay dormant for
years, till hatched under peculiarly favourable conditions; or whether
every now and then a few individuals were tempted to cross the Channel from
the Continent by some attraction unknown to us, or were, _nolens_,
_volens_, blown hith