372 
SEXUAL SELECTION. 
Part II. 
tlie same species and by their extreme diversity in 
closely-allied species— is that they have been acquired 
as ornaments. 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. 
The males of Onitis furcifer (fig. 20) 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. This 
situation seems extremely ill adapted 
for the display of these projections, 
and they may be of some real ser- 
vice ; but no use can at present be 
assigned to them. It is a highly 
remarkable fact, that although the 
Fig. 20 . onitis furcifer male, ma l es (j 0 no t exhibit even a trace of' 
viewed from beneath. 
horns on the upper surface of the 
body, yet in the females a rudiment of a single horn on 
the head (fig. 21, a), and of a crest ( b ) on the thorax, 
are plainly visible. That the slight thoracic crest in the 
Fig. 21. Left-hand figure, male of Onitis furcifer, viewed laterally. Pvight-hand figure,, 
female. a. Kudiment of cephalic horn. b. Trace of thoracic horn or crest. 
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 form 
