A juvenile male stag beetle with the scientific name Aegus chelifer chelifer,
and in Thai called
duang kihm rong kao.
It is overall black, with small grooves along the length
of its elytra (the shield-like wing caps) and large, distinctive, mandibles,
positioned horizontally. Its head and pronotum (the dorsal front part of the
thorax) have tiny indentations that, due to light, may look somewhat like
silvery spots. See also
List of Thai Insect Names.