418 DR. F. LEUTHNER ON THE ODONTOLABINI. 
Much uncertainty existed for a long time about the systematic position or, rather, 
affinities of O. wratus. Hope was misled by the unusual metallic colour of this species, 
and placed it in his ‘Catalogue’ (p. 5) between Cyclommatus tarandus and Ano- 
plocnemus ; and Prof. Westwood considered it to be nearest allied to his Lepidodes 
rotundicollis (=Cacostomus squamosus, Newm.), an Australian species’. Prof. Bur- 
meister first recognized O. wratus as an Anoplocnemus (Odontolabis), while Thomson 
and Parry (the one immediately, and the other in the second and third editions of his 
catalogue of Lucanide) 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 O. wratus. 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 (P1. XCVIL. 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, O. castelnaudi and O. 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 tibia, 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 tibia have led to its being placed in 
the genus Calcodes, Westw., with O. wratus. 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 
(Pl. XCVII. fig. 11), and its uniform pitchy black colouring, are the results of long- 
continued isolation. 
Species incerte sedis. 
O. striatus is a most exceptional form among the Odontolabini (Pl. XCVII. figs. 1-3), 
and its relationship with any of the preceding groups is very obscure. ‘The long and 
strangely shaped mandibles of the male, only the most highly developed form of which 
1 The metallic lustre (which is very slight in the female) appears strange at first sight, but is not sufficiently 
remarkable to justify the formation of a new genus. It is occasionally met with in the Lucanid, as, for 
instance, in Cyclommatus (where it is frequently wholly absent in the female), and also occurs in Chzaso- 
gnathus 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 exhibited for thirty years in the gallery of the British Museum, have become quite 
brown and bleached, like their less brightly coloured allies. 
