9 
DR. F. LEUTHNER ON THE ODONTOLABINI. 433, 
The head has no occipital crest, as in Lucanus, and no cephalic prominences, as 
in Hexarthrius; but the frontal ridge is strongly developed in large specimens; in 
small ones the head is flattened. ‘The eyes are large, and separated by a canthus of 
variable width, but narrowest in large specimens. ‘The spine behind the eye is very 
characteristic, but is scarcely developed in 0. carinatus and O. eratus. The clypeus is 
deeply emarginate, and distinctly separated from the front. The labrum projects 
between the mandibles, as far as their shape will allow, and it is frequently contracted 
into a true epistoma. The mandibles are large, and differently developed, varying 
both in shape and size. Sometimes there is an unbroken series of forms of mandibles, 
from the smallest, which resemble the female, to the largest and most highly developed ; 
but in other cases they exhibit several forms which cannot be connected by inter- 
mediate links. 
In order to facilitate comparison I have distinguished the four forms of mandibles 
which are most frequently differentiated as follows :— 
(1) Forma telodonta (+éXoc, end; odovc, tooth). The most highly developed form ; 
the terminal form!. (Pl. LXX XIX. fig. 1.) 
(2) Forma mesodonta (néooc, middle). In this form a strongly developed tooth 
projects inwards from the middle of the mandibles. (Pl. LXX XIX. fig. 3.) 
(3) Forma amphiodonta (au¢ic, on both sides), Mandibles with teeth at the tip 
and at the base only. (Pl. LX X XIX. fig. 5.) 
(4) Forma priodonta (zgiwv, saw). Inner side of the mandibles toothed. (Pl. 
LXXXIX. figs. 6, 7.) 
The second and third forms may occur conjointly (amphio-mesodonta), and the fourth 
form may be either regularly (isodont) or irregularly (anisodont) toothed. (Pl. XCIL. 
fig. 8.) 
The prothorax is generally broad, and is often provided with two or three lateral 
spines (as in QO, alces and others). It frequently happens that the middle spine only is 
developed, the sides being rounded off in many species. 
The prosternal process is generally well developed, as in 0. alces and O. dalmani, 
and projects distinctly downwards and backwards. The elytra are broad, with the sides 
margined, and are generally smooth and shining, and are most frequently black, although 
sometimes bicolorous or tricolorous. ‘The elytra are hairy in 0. dalmani, and sometimes 
in O. carinatus; in O. striatus the lines on the elytra are alternately smooth and hairy. 
O. eratus exhibits a metallic lustre. The tibiz of the long front legs are long and 
straight or slightly curved inwards. 
The small males with priodont mandibles are often so similar to the females that 
they have been frequently described as such by various authors; but they may always 
* Comp. p. 397 (antec), 
VoL. XI.—Part xt. No. 7.—November, 1885, 38 
