390 DR. F. LEUTHNER ON THE ODONTOLABINI. 
in the telodont forms of Odontolabis alces, var. dua (Pl. LXXXIX. figs. 1 
& 2), burmeisteri (Pl. XCII. fig. 5), &c. 
(4) The occipital crest is more or less developed in large specimens of Lucanus 
cervus, and in all the species of Lucanini which inhabit Europe and Asia, but 
is absent in small specimens. 
Ideal figure illustrating the modifications of the Lucanide. 
The numbers and figures correspond to the text. 
(c) The labrum. (1) In large specimens this extends straight down between the 
mandibles ; in small specimens a true triangular epistoma often becomes visible 
above the labrum (0. alces, Pl. LXXXIX. figs. 1,6). This epistoma is often 
very variable. (2) The labrum is frequently broad and quadrangular in telo- 
dont forms, but is very small in other modifications (comp. 0. brookeanus, 
Pl. XCV. figs. 13, 15). 
(d) The canthus, or rim round the eyes, is usually a constant character, and I 
hoped, like Prof. Westwood, to find it of great systematic importance. I 
examined it carefully in thousands of specimens of Lucanide, and found it 
variable only in a few species of Dorcini. In large males the eye is exposed 
(d’), but in small males and in the females it is entirely enclosed. 
(e) The spine behind the eye (a generic character), which is strongly developed in 
large specimens, is wanting in the smallest males of Odontolabis brookeanus 
and O. sommeri. 
(9) In the configuration of the prothorax (a specific character). 
(f) In the larger males of some species the sides of the prothorax are generally 
