The Descent of Man

ding what Westring has written about this beetle,
it seems very doubtful whether it possesses
any true rasp, though it has the power of emitting
a sound.
From the analogy of the Orthoptera and
Homoptera, I expected to find the stridulating
organs in the Coleoptera differing according to
sex; but Landois, who has carefully examined
several species, observed no such difference;
nor did Westring; nor did Mr. G.R. Crotch in
preparing the many specimens which he had
the kindness to send me. Any difference in these
organs, if slight, would, however, be difficult
to detect, on account of their great variability.
Thus, in the first pair of specimens of Necrophorus
humator and of Pelobius which I examined,
the rasp was considerably larger in the
male than in the female; but not so with succeeding
specimens. In Geotrupes stercorarius
the rasp appeared to me thicker, opaquer, and
more prominent in three males than in the sa-