390 DE. P. LEUTHNER ON THE ODONTOLABINI. 



in the telodont forms of Odontolabis alces, var. dux (PI. LXXXIX. figs. 1 

 & 2), hurmeisteri (PI. XCII. fig. 5), &c. 

 {b) The occipital crest is more or less developed in large specimens of Lucamis 

 cervus, and in all the species of Lucanini which inhabit Europe and Asia, but 

 is absent in small specimens. 



Fig. 1. 



Ideal figure illustrating the modifications of the Lucanidfe. 

 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, PI. 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. hrookeanus, 

 PI. 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 Lucanidse, 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), Mhich is strongly developed in 

 large specimens, is wanting in the smallest males of Odontolahis hrookeanus 

 and 0. sonimen. 

 (5) In the configuration of the prothorax (a specific character). 



(/) In the larger males of some species the sides of the prothorax ai-e generally 



