COLEOPTEKA. 



295 



tie belonging to the same great division of the Lamellicorns, the 

 males are known to fight, but are not provided with horns, though 

 their mandibles are much larger than those of the female. 



The conclusion that the horns have been acquired as ornaments 

 is that which best agrees with the fact of their having been so 

 immensely, yet not fixedly, developed, — as shown by their extreme 

 variability in the 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 stand- 

 ing 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. 21), and of 

 some other species of the genus, are furnished 

 with singular projections on their anterior fe- 

 mora, 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 rudi- 

 Fig. 21. Onitis ment of a single horn on the head (fig. 22, a), 

 furcifer, male and of a crest (b) on the thorax. That the 

 viewed from be- slight thoracic crest in the female is a rudiment 

 neath. ^^ ^ projection proper to the male, though en- 



tirely absent in the males 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, 



Fig. 22. Left-hand figure, male of Onitis furcifer, viewed laterally. 



Right-hand figure, female, a. Rudiment of cephalic horn. 



b. Trace of thoracic horn or crest. 



and the male bears a great projection in the same situa- 

 tion. 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 Ph^insus (fig. 18). 

 The old belief that rudiments have been created to complete the 



