THE LAMELLICORNIA, OR “ CHAFERS.” 157 
and small or feebly developed males exhibiting but a 
weak edition of the normal projections. 
All these insects hum considerably in flight, and 
possess the power of making a stridulating noise, 
which is caused by the friction of a transversely 
striated elevation on the posterior border of the 
hinder coxa against the hinder margin of the 
acetabulum into which it fits. 
Although naturally feeders on animal excrement, 
some species (e.g. Geotrupes vernalis ) are often found 
in rotten fungi. 
The Trogina have five ventral segments to the 
abdomen (except in some species of Trox, where there 
is an indication of a sixth), but slightly moveable ; 
the anterior legs are not fossorial, the tibiae not being 
enlarged, or strongly toothed ; the antennas ten- 
jointed ; scutelluin small ; the coxae contiguous, 
those of the front and intermediate legs being- 
very short (the latter almost globose, and scarcely 
at all oblique) ; the elytra entirely cover the ab- 
domen ; and the mandibles aud labrum are un- 
covered by the clypeus. 
We possess but one genus, Trox ; of which the 
species are rather rare. They are dull black, mode- 
rately large, oblong, of strong integuments, and usually 
with interrupted rows of short pencils of bristles on 
the elytra. When seized they make a squeaking- 
noise by rubbing the abdomen against the elytra, and 
contract their limbs. They are found in sandy places, 
in half-dry carcases, of which they consume the harder 
portions; in rams’ horns, &c. Some of them have 
imperfectly developed wings, the others appearing to 
fly only in the evening ; aud certain exotic species 
