perceptible on the front
wing, and there is a distinct _white_ spot in the centre of the front
wings. The _under side_ also is precisely like that of Agestis, with the
black spots removed from the centre of the white rings, which are thus
changed into _large white spots_, as shown in the figure.

There has been a great deal of discussion among entomologists, as to
whether this be a distinct _species_, or only a variety of _Agestis_. I
believe it to be the latter, but do not attach much importance to the
question; and as this butterfly is found under the name of _Artaxerxes_, in
almost every cabinet, and is rather a famous little insect, I have thought
it best to give it a separate heading under its usual title, and collecting
readers may still label it in their cabinet either as above, or as "_P.
Agestis, var. Artaxerxes_," and probably will be equally right either way.

The popular nature and limited extent of this work will not, however, admit
of the subject being entered into scientifically, and I can only here state
that I have {162} seen specimens from various parts of the country, that
include every intermediate variety between the ordinary _Agestis_ of the
south, and the _Artaxerxes_ of Scotland. The Durham Argus, formerly called
_P. Salmacis_, forms one of these gradations.

Against the idea of _Agestis_ and _Artaxerxes_ being one species, it has
been objected, that the former is double, the latter single brooded. What
of that? Plenty of species that are double-brooded in the south of Europe
are well known to become single-brooded in a more northern situation.

The _caterpillar_ is said to be exactly like that of _Agestis_. It feeds on
_Helianthemum vulgare_ (Rock Cistus).

The _butterfly_ is found in July and August in several parts of Scotland,
and the north of England. Arthur's Seat, Edinburgh, has been long noted for
producing it.

[Illustration: XIV.]

{163}

THE SKIPPERS. (Family--_Hesperidae_.)

These curious little butterflies form a very natural group; in many
respects, both of structure and habits, approaching the moths, and
therefore placed at the end of the butterflies. They are of small size, but
robust appearance, and not brightly coloured. Their flight is rapid, but of
short continuance, and they seem to _skip_ from flower to flower: hence
their name. They are chiefly distinguished scientifically from other
butterflies by the form of the _antennae_, which are more or less hooked at
the