| abstract | The following species are described as new to science, Ichoronyssus orcadensis, Coproholaspis anglicus and Spinturnix omahonyi as well as Trombidium holosericeum var. septentrionalis var. nov. The Haemogamasus arvicolarum (Berl.) is restudied and redescribed besides being recorded for the first time from Britain. The following new species to the British acarine fauna are recorded: Periglischrus rhinolophinus (Koch), Phaulocylliba romana (G. and R. Can.), Cheyletes schneideri Oudms., Trombidium mediterraneum (Berl.), Calyptostoma lynceum (Berl.), Belaustium murorum (Herm.) and Caloglyphus rodionovi Zach. The male of Spinturnix plecotinus (Koch) is described for the first time. An extended study is made of the British species of the genera Ichoronyssus, Spinturnix, Coproholaspis, and Calyptostoma, together with dichotomic keys. The forms of Pergamasus crassipes var. longicornis Berl. are discussed and a new extreme variation described. Biological notes on the mating of feather mites and on the mites causing chorioptic mange in the horse are given. Notes are appended on other little known species of mites recorded from the British Isles. |