The Genera Ideobisium and Ideoblothrus, with Remarks on the Family Syarinidae (Pseudoscorpionida)

Ideobisium Balzan and Ideoblothrus Balzan are redefined after examination and redescription of the types, Ideobisium crassimanum Balzan and Ideoblothrus similis Balzan. Pachychitra Chamberlin is shown to be a synonym of Ideoblothrus. All known species of each genus are listed and doubtful species are discussed; Ideobisium balzanii With and Ideoblothrus seychellesensis (Chamberlin) are redescribed; and the following new species are described: Ideobisium chapmani, I. peckorum, I. ecuadorense, I. puertoricense, I. yunquense, and Ideoblothrus kochalkai, I. colombiae. The assignment of these genera to the family Syarinidae is discussed.