Gynaecoserica tumba is a species of beetle of the family Scarabaeidae. It is found in western Sikkim.
Adults reach a length of about 5.4âÂÂ6 mm. They have a light brown, elongate-oval body. The sides of the elytra, as well as some small spots on the elytra are darker and the pronotum has a slightly green metallic sheen. The upper surface is dull with some hairs except on the shiny forehead.
The species name is derived from the Sikkimese Bhutia language word Tumba (the beer brewed by local monks).