418 DR. F. LEUTHNEE ON THE ODONTOLABINI. 



Much uncertainty existed for a long time about the systematic position or, rather, 

 affinities of 0. wratus. Hope was misled by the unusual metallic colour of this species, 

 and placed it in his 'Catalogue' (p. 5) between Cyclommatm tarandus and Ano- 

 plocnemus ; and Frof. Westwood considered it to be nearest allied to his Lepidodes 

 rotundicolUs { = Cacostomus squamostis, Newm.), an Australian species ^ Prof Eur- 

 meister first recognized 0. (eratiis as an Anoplocnemus (Odontolabis), while Thomson 

 and Parry (the one immediately, and the other in the second and third editions of his 

 catalogue of Lucanida?) referred it to Westwood's subgenus Calcodes. 



The more our knowledge was increased by the discovery of new species, the easier it 

 became to perceive the real affinities of 0. ceratus. If we pass over its metallic lustre 

 and small size, and pay attention to the structure of the female, we are obliged to 

 admit that its morphological characters agree perfectly with those of Section B. The 

 strongly curved mandibles in the telodont form (PI. XCVII. fig. 4) and the small eleva- 

 tion between the apical group of teeth and the central tooth, are very similar to those 

 of its allies, 0. castelnaudi and 0. sommeri, which occur in adjacent countries. It is 

 likewise related to them by the broad clypeus and hairy mentum (only observed and 

 described by Westwood), the long curved front tibias, considerably widened on the 

 inside at the tip, and the very hairy tarsi of all the legs. 



As Parry had already suspected, 0. carinatus, Linn, {nigritus, Deyr.), which occurs 

 both on the east coast of India and in Ceylon (comp. Map III. p. 417), is nearly related 

 to the present group. The form of the head (owing chiefly to the absence of the spine 

 behind the eyes in the male) and the long front tibiae have led to its being placed in 

 the genus Calcodes, Westw., with 0. ceratus. Traces of its relationship to its eastern 

 progenitor may be found in the remarkable hairiness of the mentum and gula (fig. 12, 

 c) and the thick silky hair of the tarsi ; but the considerable deviation of the male 

 mandibles, the disappearance of the broad quadrangular clypeus in the telodont form 

 (PI. XCVII. fig. 11), and its uniform pitchy black colourmg, are the results of long- 

 continued isolation. 



Species incertoe sedis. 

 0. striatus is a most exceptional form among the Odontolabini (PL XCVII. figs. 1-3), 

 and its relationship with any of the precedmg groups is very obscure. The long and 

 strangely shaped mandibles of the male, only the most highly developed form of which 



^ Tho metallic lustre (which is very slight in the female) appears strange at tirst sight, but is not sufficiently 

 remarkable to justify the formation of a new genus. It is occasionally met with in the Lucauidac, as, for 

 instance, in Ci/dommattts (where it is frequently wholly absent in the female), and also occurs in C/iiaso- 

 gnaihus and Lamprima. Several authors have supposed that this metallic lustre is due to the direct effect of 

 the sun's rays, as these beetles are active in broad day ; but it is certain that this lustre, although unaffected 

 by acid, disappears when dead specimens are exposed to sunlight. Specimens of the beautiful gold-shining 

 Chiasognathus, which were exliibitcd for thirty years in the gallery of the British Museum, have become quite 

 brown and bleached, like their less brightly coloiired allies. 



