These varieties are very scarce, but both are also mimicked
elsewhere by the female Hypolimnas. The same thing
occurs in India, where, however, the mimicker of the
var. dorippus is somewhat abundant, while the mimicked
form is very seldom seen. Thus we have a butterfly
mimicking a form which is almost extinct, and to a
superficial observer weakening the theory which explains
these anomalies. But it is necessary in all these cases
to carry the mind back to the time when the butterflies,
like all other living forms, were slowly establishing
themselves by those qualities and appearances which,
under the law of natural selection, enabled them to
survive the struggle for existence. It was then that
what we call “ mimicry ”—which is only one of a multitude
of laws which govern the coloration of animals—first
arose, and butterflies which slightly resembled uneatable
species, or had somewhat the appearance of inanimate
objects, would escape perils common to their kind, and
these would thus become the dominant breed of the
species, and be continually under the same selective
process, till the disguise was almost perfect. If, then,
we now find the present scarce form of the species so
largely mimicked, it seems absolutely certain by the survival
of the mimicry that it must have been once the
dominant form of the species—at least in India—and
has since, in the recurrent changes of nature, been
almost replaced by the present form we so well know *.
The food-plant of this butterfly (Gomphocarpus, sp.),
which grows and blooms upon the most dry and barren
parts of the veld as well as where moisture is found,
is universally distributed in patches or small groups
and is one of the earliest plants to spring up and
bloom when the cold nights of the dry season become
less severe. Its flowers are visited by many insects.
From them I have collected some half-dozen species
of Cetowia and some showy representatives of the
Heteromera, as well as Gallerucidse and Coccinellidse.
Many Diptera and Hymenoptera visit the bloom,
* For these views regarding the evolution of the species in India, I am
largely indebted to Colonel Swinhoe, the well-known Indian lepidopterist.
and among Hemiptera a species of Lygaeas is particularly
abundant.
At about the end of November the shrill cry of the
Cicadas was constantly heard from the willow and peach-
trees in Pretoria, but principally from the first. The
dominant species was Platypleura divisa, and I was
surprised to find that it was captured and eaten by
spiders. On once hearing a particularly loud chorus
from a peach-tree, I visited the same to capture
specimens, and found that spiders had industriously
spread their webs between the branches, and remains of
the Platypleuroe were suspended in a more or less devoured
condition. I made use of these webs to procure
specimens, for when first disturbed the flight of the
Platypleuroe is wild and headlong, but by getting
between them and the meshes of the spiders I was
soon enabled to obtain what was required. I t is
reasonable to believe that these insects pair during
their mature stages or breeding-season. We passed
daily a small willow tree where I constantly noticed
a solitary couple of the species, and this was also
known by the fact that we drove them out on walking
by and frequently endeavoured to capture them. The
male was always tuning, and was probably addressing
his mate. At length, unfortunately, the singer allowed
us to capture him; the tree was henceforth mute, and
I afterwards felt quite a remorse when my path took
me by the then silent. Cicadan home, for there was not
the consolation of having captured either a new species
or one new to my collection.
I was surprised to find how many living creatures
one had known in Britain were also to be found in the
Transvaal. In birds the European Bee-eater (Merops
apiaster) and Montagu’s Harrier (Circus pygargus) were
not at all uncommon, whilst in insects one was continually
meeting with some old friend. A List is appended to
this volume of all these comrades one finds across the
sea, or rather near the extremity of another continent;
but with fixed ideas of geographical distribution, and
our natural conception of an Ethiopian region, it was
F 2