40 LAMELLICORNIA. | Geotrujina. 
GEOTRUPINA. 
The species belonging to this tribe are, as a rule, of large size and 
rounded convex form; in some species the males have the thorax, and 
sometimes the head, armed with horns and tubercles; the antenne are 
11-jointed, and terminate in a 3-jointed club, which is variable in form; 
the ventral segments are six in number, and the pygidium is covered hy 
the elytra; four genera are found in Europe, of which two occur in 
Britain; three or four other tribes intervene between the Aphodiina and 
the Geotrupina, of which the Hybalina and Hybosorina oecur in Europe, 
but are not represented in our fauna. 
I. Antenne with club longer than funiculus, not lamellate ; 
posterior angles of thorax right angles; size smaller . . . ODONTEUS, Klug. 
II. Antennz with club shorter than funiculus, lamellate ; pos- : 
terior angles of thorax obtusely rounded; size larger. . . GxorrupsEs, Latr, 
ODONTEWUS, Klug. 
The three or four species that form this genus have been by many 
authors included under the genus Bolboceras, Kirby, which contains 
upwards of a hundred species that are widely distributed throughout the 
world; the species belonging to Odonteus proper have been described 
from North America and Europe, and appear to be distinguished by 
having the eyes entirely divided instead of only partially divided as in 
Bolboceras ; the single European species is extremely rare in Britain, 
and may be at once known from Geotrupes by its smaller size, the long 
club of the antenne, the right-angled posterior angles of thorax, and the 
long recurved moveable horn on the head of the male; it lives in dung, 
but has usually been taken in Britain on the wing. 
O. mobilicornis, I’. (armiger, Scop.; 3 bicolor, F.). Short oval, very 
convex, upper surface glabrous, colour black or pitchy, occasionally, in 
immature specimens, feriuginous, under-side reddish or brownish-yellow, 
clothed with yellowish pubescence; head thickly and rugosely punctured 
in front; thorax punctured, with a fine longitudinal channel in centre 
which is abbreviated in front, posterior angles right angles; elytra with 
strong punctured stria, interstices impunctate or almost impunctate ; 
antenne and legs yellowish, tibie darker, front tibie with eight teeth. 
L. 6-8 mm. 
Male with an elongate, curved, moveable horn on forehead; thorax in 
front horned and foveolate on each side, and furnished with two teeth in 
the centre. 
Female with two feeble prominences on forehead, and three on the 
front of thorax. 
Tn small males the horn on forehead is much shorter, and the horns 
and foyesx on thorax are more or less obsolete. 
