Maechidius ursus is a species of beetle of the family Scarabaeidae. It is found in Indonesia (Misool), where it occurs in primary lowland rainforests.
Adults reach a length of about 8.60 mm. The dorsum and venter are uniformly dark brown and covered with microscopical velvety pubescence. The mouthparts, antennae and legs are reddish brown.
The species name is derived from Latin ursus (meaning bear) and refers to the robust body and peculiar, dense, mammal-fur-like pubescence.