Review of the mite genus Ololaelaps (Acari, Laelapidae) and redescription of O. formidabilis Berlese

: A species of laelapid mite, Ololaelapsformidabilis, is redescribed based on male and female adults from soil in Sumatra, Indonesia. This species is distinguished from other Ololaelaps species by its metapodal platelet narrowly fused with the parapodal plate and by its hologastric shield having two inverted-V-like ridges. The genus is redescribed based on a review of the literature and examination of specimens of some species. Valid species of Ololaelaps are listed and accompanied by notes on morphological characters to assist future revision of the genus.