Odontolabis castelnaudi is a beetle of the family Lucanidae. It is known from Borneo (Sabah, Malaysia) and Sumatra (Indonesia).
Odontolabis castelnaudi can grow to in length. It is mostly black but has yellow wings sheaths.
References
Further reading Lacroix, J.-P., 1984. The Beetles of the World, volume 4, Odontolabini I (Lucanidae) – Genera Chalcodes, Odontolabis, Heterochtes. This is a very good revision of the genus Odontolabis