Chap. X. 
COLEOPTERA. 
375 
Professor Westwood states, “ in which the central horn 
“ of the thorax is very large, but the horns of the head 
“ quite rudimental; and others, in which the thoracic 
“horn is much shorter, whilst the protuberances on 
66 the head are long .” 62 Here, then, we apparently 
have an instance of compensation of growth, which 
throws light on the curious case just given of the loss of 
the upper horns by the males of Onitis furcifer. 
Laiv of Battle . — Some male beetles, which seem ill 
fitted for fighting, nevertheless engage in conflicts for 
the possession of the females. Mr. Wallace 63 saw two 
males of Leptorhynchus angustatus , a linear beetle with 
a much elongated rostrum, “ fighting for a female, who 
“ stood close by busy at her boring. They pushed at 
“ each other with their rostra, and clawed and thumped, 
“ apparently in the greatest rage.” The smaller male, 
however, “ soon ran away, acknowledging himself van- 
“ quished.” In some few cases the males are well 
adapted for fighting, by possessing great toothed man- 
dibles, much larger than those of the females. This 
is the case with the common stag-beetle ( Lucanus 
eervus ), the males of which emerge from the pupal state 
about a week before the other sex, so that several may 
often be seen pursuing the same female. At this period 
they engage in fierce conflicts. When Mr. A. H. 
Davis 64 enclosed two males with one female in a box, 
the larger male severely pinched the smaller one, until 
he resigned his pretensions. A friend informs me 
62 ‘Modern Classification of Insects,’ vol. i. p. 172. On the same 
page there is an account of Siagonium. In the British Museum I 
noticed one male specimen of Siagonium in an intermediate condition, 
so that the dimorphism is not strict. 
63 ‘ The Malay Archipelago/ vol. ii. 1869, p. 276. 
64 ‘ Entomological Magazine,’ vol. i. 1833, p. 82. See also on the 
conflicts of this species, Kirby and Spence, ibid. vol. iii, p. 314 ; and 
Westwood, ibid. vol. i. p. 187. 
