Two new soil-dwelling psocids (Psocoptera: Trogiidae and Pachytroctidae) from the islands of St Helena and Madagascar

Two new apterous species of Psocoptera (Insecta) are described and illustrated, each belonging to a new genus: Helenatropos abrupta gen. n., sp. n. (female) (Trogiidae) from a semidesertic biotope on the mid-Atlantic island of St Helena, and Thoracotroctes spinifer gen. n., sp. n. (male) (Pachytroctidae) from the endemic Didiereaceae vegetation in southern Madagascar. The systematic positions of the new genera within their families are discussed and a new subfamily is defined for Thoracotroctes gen. n.: Thoracotroctinae subfam. n. A key to the subfamilies of Pachytroctidae is provided.