same species, and by their extreme diversity in closely-allied species.
This view will at first appear extremely improbable; but we shall
hereafter find with many animals standing much higher in the scale,
namely fishes, amphibians, reptiles and birds, that various kinds of
crests, knobs, horns and combs have been developed apparently for this
sole purpose.
[Fig.21. Onitis furcifer, male viewed from beneath.
Fig.22. Onitis furcifer. Left-hand figure, male, viewed laterally.
Right-hand figure, female. a. Rudiment of cephalic horn. b. Trace of
thoracic horn or crest.]
The males of Onitis furcifer (Fig. 21), and of some other species of
the genus, are furnished with singular projections on their anterior
femora, and with a great fork or pair of horns on the lower surface of
the thorax. Judging from other insects, these may aid the male in
clinging to the female. Although the males have not even a trace of a
horn on the upper surface of the body, yet the females plainly exhibit
a rudiment of a single horn on the head (Fig. 22, a), and of a crest
(b) on the thorax. That the slight thoracic crest in the female is a
rudiment of a projection proper to the male, though entirely absent in
the male of this particular species, is clear: for the female of Bubas
bison (a genus which comes next to Onitis) has a similar slight crest
on the thorax, and the male bears a great projection in the same
situation. So, again, there can hardly be a doubt that the little point
(a) on the head of the female Onitis furcifer, as well as on the head
of the females of two or three allied species, is a rudimentary
representative of the cephalic horn, which is common to the males of so
many Lamellicorn beetles, as in Phanaeus (Fig. 18).
The old belief that rudiments have been created to complete the scheme
of nature is here so far from holding good, that we have a complete
inversion of the ordinary state of things in the family. We may
reasonably suspect that the males originally bore horns and transferred
them to the females in a rudimentary condition, as in so many other
Lamellicorns. Why the males subsequently lost their horns, we know not;
but this may have been caused through the principle of compensation,
owing to the development of the large horns and projections on the
lower surface; and as these are confined to the males, the rudiments of
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